A float is stuck (cannot be placed)

Question

I am writing an article using revtex4-1, and I am facing the following warning:

MnBi.bbl|1 warning| LaTeX Warning: A float is stuck (cannot be placed) on input line 1.

(As from vim's quickfix output, using latexmk)

My bib file is fine and it is compiled fine using bibtex. I tried to create a minimal example, but unable to reproduce the warning.

Also, while running pdflatex, I get same warning, but for different position, as:

Underfull \hbox (badness 10000) in paragraph at lines 322--323
[]\OT1/cmr/m/n/10 This work is sup-ported by EP-SRC grant
(./MnBi.bbl [2 <./images/cellE.png> <./images/Perfect_anisotropy.png> <./images
/Mn_ExcessT.png>]
LaTeX Warning: A float is stuck (cannot be placed) on input line 1.
LaTeX Warning: A float is stuck (cannot be placed) on input line 1.
Class revtex4-1 Warning: Deferred float stuck during \clearpage processing.

How can I get rid of this warning?

edit: This is said in the Revtex Manual:

Sometimes in L A TEX the float placement mechanism
breaks down and a float can’t be placed. Such a “stuck”
float may mean that it and all floats that follow are moved
to the end of the job (and if there are too many of floats,
the fatal error Too many unprocessed floats will oc-
cur). REVTEX 4 provides the class option floatfix
which attempts to invoke emergency float processing to
avoid creating a “stuck” float. REVTEX 4 will provide
a message suggesting the use of floatfix. If floatfix
doesn’t work or if the resulting positioning of the float is
poor, the float should be repositioned by hand.