You seem to be running mimetex on a different machine than it was compiled on. In particular, a machine with a different version of the C-library. That's almost surely your problem. To solve it, you need mimetex compiled with the library functions built-in.
Did you compile mimetex yourself? If so, add the -static switch to your compile line, i.e.,
cc -static -DAA mimetex.c gifsave.c -lm -o mimetex.cgi
(or -o mimetex.linux if you're really calling your executable image mimetex.linux).
Or did you download a pre-compiled version? In that case, you seem to have downloaded one compiled without the -static switch. Scroll to the bottom of the QuickBuild Section on http://www.forkosh.com/mimetex.html and click the linux link to download a zip file containing pre-compiled executable mimetex.cgi which should work for you (and rename/mv it to mimetex.linux if required).