I suspect there re no longer nightly builds for Mono, the code has some Win32 API calls.

Instructions

Detailed instructions

You probably have Mono already installed. Try running 

mono --version

If it complains about "no such file or directory", or the version reported is lower than 1.9.1, use your system package manager to install a recent release of Mono.

Caveats

This is a nightly build, so it may break after any new commits. It probably won't work on Microsoft .Net Framework. I'm currently using http://evemon.battleclinic.com/snaps_mono/2008-06-22_rev_1200_compiled.zip on Gentoo + Mono 1.9.1 and it is fairly stable - but not without glitches. Please remember that EVEMon is not officially supported on Linux and any bugs that are Mono-specific will be given low priority. If you are able to provide patches improving EVEMon behaviour on Mono - either fixing bugs in EVEMon code or in Mono - please do. Bug reports on Mono Bugzilla (if you can extract a test case from EVEMon sources) are also a great way to help. For ideas what needs improvement - look below.

Known issues