I installed MiKTeX and TeXnic-Center. I then installed the typesetting of my university (here: http://tubslatex.ejoerns.de/#releases).
I then compiled the .cls-file of the template from the institute with TeXnic(www.winfo.tu-bs.de/hp/upload/vorlagen/ds_latex_seminar.zip). At this point the following warnings and errors appeared:
- "You have requested package
', but the package providesunitext'" - Command \@ already defined
- Missing \bein{document}
- Missing number, treated as zero
- You already have nine parameters
- Command \@already definied. Or name \end... illegal
- Font shape
/cmr/m/n' undefined using/cmr/m/n instead on input line - The font size ommand \normalsize is not defined
- [...]
When trying to preview the unitext.dvi with the app YAP the following error message appeared: "Not loadable Fonts: ec-lmr12, ec-lmssbx10, ec-lmss12, ec-lcssby19"
Here is what I have already tried:
1) I installed the typesetting of the university (see above) manually (meaning I put the folders of the TDS-archive in the right places) and automatically.
2) I used the MiKTeX-Packagemanager to install all(!) packages including the following strings: "lm". I understand that "lm" means latin modern.
3) I used the command (in admin mode): "initexmf --mkmaps"
4) I used the command (in admin mode): "updmap ec-lmr12.tfm".
The first time this command seemed to work (didn't return error message in the console), but it didn't solve the problem that the fonts are not loading.
Second time: After deinstalling everything and doing it all over again the following error message was returned by the console:
"log4cxx: No appender could be found for logger .
log4cxx: Please initialize the log4cxx system properly.
Sorry, but the "MiKTeX Fontmap Maintenance Utility did not succeed for the following reason: This utility does not accept non-option arguments.
[...]"

Do you have any idea why the fonts are still not loading? I already tried so much and it is still not working, so I would appreciate your help very much!

kpsewhich ec-lmr12.tfmreturn? You'll need to get a command line prompt to run this. If that gives you the location of the file, it is likely that you need to runupdmapas yourself and/or with admin rights. MiKTeX doesn't always update the font maps when new font packages are installed. – cfr Dec 04 '15 at 20:49However, when viewing the .dvi file with the Yap-viewer the error message is still appearing as before. Still, four fonts are not loadable.
But thank you really much for your help and time!
– user5569792 Dec 04 '15 at 21:20