I upgraded to the git/master a few days ago, and notice that running imaxima withing emacs no longer works. Specifically, all equations report as latex errors. After looking at the tex files generated by imaxima, I realized that all off the \usepackage directives were missing, in particular color and breqn. I copied the preamble used in other parts of imaxima.el and things now work, except for ultra-long equations (which were broken for some time). I've attached a patch file.
Thanks for the report and the patch. I've applied the patch as commit [873f253] and imaxima seems to work as expected. Closing this report.
I have to wonder how it ever worked, but I'm not wondering too much ... I'm happy enough that it works now.