For this task you will need to pick a bug, issues or missing feature from the application's bug tracker and fix it.  

You can not create a new bug ticket yourself to fix, apart from if you picked this application for "test for bugs and issues task", so you will have to pick one from the list. 

There are so many different types of bugs and issues, so no extra details can be given here. If you have a question, just ask here or on the bug tracker.

http://developer.berlios.de/bugs/?group_id=5154

http://dev.osdrawer.net/projects/pe-editor/issues