Paragraph ended before \@lbibitem was complete error

Question

I've happily typing up my report and including references when suddenly it refuses to compile and outputs C:\Users\User\Documents\Project work\Latex Report\Main\master.bbl:53: Paragraph ended before \@lbibitem was complete. [].

I've searched through my bib file and there is no error and the entry DOES exist. When I take after the offending citep{....} it works again! I've tried deleting the temp files but to no avail!

Any ideas?

MWE:

\documentclass[12pt, preprint]{aastex}
\begin{document}
\citep{zou_sky_2010}
\bibliographystyle{mn2e}
\bibliography{zotero}
\end{document}

and here is the bib file entry (it works for other citations before the zou one):

@article{aragon-salamanca_measuring_2006,
    title = {Measuring the fading of S0 galaxies using globular clusters},
    volume = {458},
    issn = {0004-6361, 1432-0746},
    url = {http://arxiv.org/abs/astro-ph/0607645},
    doi = {10.1051/0004-6361:20065948},
    abstract = {We test the hypothesis that S0 galaxies are the descendants of fading spirals whose star formation has been shut down, by using the properties of their globular cluster ({GC)} systems. We estimate the amount by which the {GC} specific frequency (number of {GCs} per unit V-band luminosity) is enhanced in S0s relative to spirals. If the transformation hypothesis is correct, and no {GCs} are created or destroyed in the process, then this difference provides a measure of the degree to which the S0's V-band luminosity has faded relative to that of its spiral progenitor. We also explore whether the degree to which the {GC} specific frequency is enhanced in S0s correlates with the colour of the stellar population, as also predicted by this hypothesis in which galaxies become redder as they fade. We find that, on average, the {GC} specific frequency is a factor {\textasciitilde}3 larger for S0s than for spirals, which can be interpreted as meaning that passively-evolving S0s have faded by about a factor of 3 from their spiral progenitors. This value fits remarkably well with the predictions of stellar population synthesis calculations, and the offset between the S0 and spiral Tully-Fisher relations. We also find that the global colours of S0 galaxies are strongly correlated with their {GC} specific frequencies: the redder the stellar population of an S0, the larger its specific frequency, as we might expect if we are catching different S0s at different stages of passively fading and reddening. Comparison to the predictions of stellar population synthesis models show that this explanation works quantitatively as well as qualitatively. These tests strongly support the hypothesis that S0 galaxies were once normal spirals, whose star formation was cut off, presumably due to a change of environment.},
    number = {1},
    urldate = {2014-02-21},
    journal = {{A\&A}},
    author = {Aragon-Salamanca, A. and Bedregal, A. G. and Merrifield, M. R.},
    month = oct,
    year = {2006},
    note = {{arXiv:astro-ph/0607645}},
    keywords = {Astrophysics},
    pages = {101--105},
    file = {arXiv.org Snapshot:C:\Users\User\AppData\Roaming\Zotero\Zotero\Profiles\1lsc8c6m.default\zotero\storage\EGF2HBU9\0607645.html:text/html;astro-ph/0607645 PDF:C:\Users\User\AppData\Roaming\Zotero\Zotero\Profiles\1lsc8c6m.default\zotero\storage\SDKMTE4D\Aragon-Salamanca et al. - 2006 - Measuring the fading of S0 galaxies using globular.pdf:application/pdf}
}

@article{zou_sky_2010,
    title = {The sky brightness and transparency in i-band at Dome A, Antarctica},
    url = {http://arxiv.org/abs/1001.4951},
    abstract = {The i-band observing conditions at Dome A on the Antarctic plateau have been investigated using data acquired during 2008 with the Chinese Small Telescope {ARray.} The sky brightness, variations in atmospheric transparency, cloud cover, and the presence of aurorae are obtained from these images. The median sky brightness of moonless clear nights is 20.5 mag arcsec{\textasciicircum}\{-2\} in the {SDSS} \$i\$ band at the South Celestial Pole (which includes a contribution of about 0.06 mag from diffuse Galactic light). The median over all Moon phases in the Antarctic winter is about 19.8 mag arcsec{\textasciicircum}\{-2\}. There were no thick clouds in 2008. We model contributions of the Sun and the Moon to the sky background to obtain the relationship between the sky brightness and transparency. Aurorae are identified by comparing the observed sky brightness to the sky brightness expected from this model. About 2\% of the images are affected by relatively strong aurorae.},
    urldate = {2014-03-27},
    journal = {{arXiv:1001.4951} [astro-ph]},
    author = {Zou, Hu and Zhou, Xu and Jiang, Zhaoji and Ashley, M. C. B. and Cui, Xiangqun and Feng, Longlong and Gong, Xuefei and Hu, Jingyao and Kulesa, C. A. and Lawrence, J. S. and Liu, Genrong and Luong-Van, D. M. and Ma, Jun and Moore, A. M. and Qin, Weijia and Shang, Zhaohui and Storey, J. W. V. and Sun, Bo and Travouillon, T. and Walker, C. K. and Wang, Jiali and Wang, Lifan and Wu, Jianghua and Wu, Zhenyu and Xia, Lirong and Yan, Jun and Yang, Ji and Yang, Huigen and Yao, Yongqiang and Yuan, Xiangyan and York, D. and Zhang, Zhanhai and Zhu, Zhenxi},
    month = jan,
    year = {2010},
    keywords = {Astrophysics - Instrumentation and Methods for Astrophysics},
    file = {1001.4951 PDF:C:\Users\User\AppData\Roaming\Zotero\Zotero\Profiles\1lsc8c6m.default\zotero\storage\ZPP55GBQ\Zou et al. - 2010 - The sky brightness and transparency in i-band at D.pdf:application/pdf;arXiv.org Snapshot:C:\Users\User\AppData\Roaming\Zotero\Zotero\Profiles\1lsc8c6m.default\zotero\storage\4NKTSGT6\1001.html:text/html}
}

@article{pohlen_outer_2002,
    title = {Outer edges of face-on spiral galaxies. Deep optical imaging of {NGC} 5923, {UGC} 9837 and {NGC} 5434},
    volume = {392},
    issn = {0004-6361},
    url = {http://adsabs.harvard.edu/abs/2002A%26A...392..807P},
    doi = {10.1051/0004-6361:20020994},
    abstract = {We present deep optical imaging of three face-on disk galaxies together 
with a detailed description of the reduction and calibration methods
used, in order to measure the intrinsic shape of their outer stellar
edges. Whereas it is now well accepted that disks of spiral galaxies are
not infinite exponential beyond galactocentric distances of about 3-5
radial scalelengths, the genuine structure of the truncation region is
not yet well known. Our data quantitatively establish a smooth
truncation behaviour of the radial surface brightness profiles and is
best described by a two-slope model, characterised by an inner and outer
exponential scalelength separated at a relatively well defined break
radius. This result disagrees with the frequently assumed sharply
truncated nature of the radial surface brightness profiles and implies
the presence of stars and even star-formation beyond the break radius.
In addition, we do not find a strong influence of a nearby companion on
the ratio of the break radius to the radial scalelength. Our results
denote new observational constraints for the search of the physical
explanation for these smooth disk truncations. Based on observations
obtained at the German-Spanish Astronomical Center ({DSAZ)}, Calar Alto,
jointly operated by the Max-Planck-Institut f{\"u}r Astronomie
Heidelberg and the Spanish National Commission for Astronomy.},
    urldate = {2014-02-26},
    journal = {{A\&A}},
    author = {Pohlen, M. and Dettmar, R.-J. and L{\"u}tticke, R. and Aronica, G.},
    month = sep,
    year = {2002},
    keywords = {galaxies: fundamental parameters, galaxies: individual: {NGC} 5923, galaxies: spiral, galaxies: structure, {NGC} 5434, {UGC} 9837},
    pages = {807--816},
    file = {NASA/ADS Full Text PDF:C:\Users\User\AppData\Roaming\Zotero\Zotero\Profiles\1lsc8c6m.default\zotero\storage\2VQC2SMP\Pohlen et al. - 2002 - Outer edges of face-on spiral galaxies. Deep optic.pdf:application/pdf}
}