robert-kuropkat,
MyEclipse doesn’t provide an integrated support for RSSOwl Plugin.Can you give me some information to investigate the error.
1) Can you copy and paste your installation details? You can get it from MyEclipse > Installation Summary > Installation Details
2) Can you copy and past your myeclipse log messages?Your error log file is located at [your workspace dir]/.metadata/.log
The important thing is to verify the compatibility factor. Verify that RSSOwl Plugin you are trying to install as a plugin to your MyEclipse version is compatibvle to the base Eclipse version.I can suggest you try to install it on your base eclipse,if you find RSSOwl Plugin compatible with your base eclipse.