I can confirm this bug. It seems that it happens when you check "examples" for rebuilding in Lazarus' rebuild dialog. Only in trunk version of Lazarus. Some example application replaces Lazarus IDE.

I reproduced it with Win XP, Lazarus 0.9.31, win32/64 ws.
In Ubuntu I wasn't able to reproduce it, so it seems to be Windows only bug.
I am going to make bug report.
To make your Lazarus usable now, rebuild Lazarus from command line with "make clean all", then start it, uncheck "examples" and rebuild.