Hello all,
I just installed monodevelop from the mono repositories. When i click to start the program i get this error:
http://img708.imageshack.us/img708/3796/snapshot8t.png
I use openSUSE 12.1 x64 KDE4.8.1 from the upstream repositories.
Anyone solved this problem? 
IMO,
I haven’t looked at MonoDevelop for a couple years now,
I wasn’t happy then that it was so buggy, there wasn’t an integrated debugger and they were missing all their roadmap milestones.
On the face of it, your error looks like a fundamental coding dotNET coding error (yes, I’m guessing without putting any real effort into looking at the error more closely), I don’t think it’s the type of error that can be resolved by an End User. Also, unless there was error in compilation, this type of error isn’t normally distro-specific.
Recommend you take a look at the history of the current version (ie How old is it? Has there been any recent updates? Has this been reported in a Bugzilla?).
Good Luck,
TS
Late reply I know, but may be useful for others: You need to install package libgnomeui (reference: http://8thstring.blogspot.co.uk/2013/01/the-following-add-ins-could-not-be.html). This fixed the issue for me on opensuse 13.1, KDE, mono develop 5.0.1.