the -agentlib:yjpagent is in the idea.exe.vmoptions.
I have replaced the jre included ithe idea version,.. and it did't start because of this line.
It means that the yourkit profiler was running with this version.
Removing the line in the idea.exe.vmoptions file and using jre 1.5.06 may solved my problem.
By the way the library is available in current 6.0.2 distribution.