Error saving customized WorkItem

Hi,

I'm using RTC2.0.0.2iFix4 with Jazz-Server: Express-C

I've tried to create a new WorkItemType on com.ibm.team.workitem.workItemType in the ProcessConfiguration
with some custome attributes by duplicate and editing from the existing workitems.
At doing this, I've also edited the predefined Types, but have undo the changes (I think so).
Now I'm unnable to save WorkItems in this ProjectArea.

Error running operation 'Saving Work Item'

Problem
An error occurred during "Save Work Item".

java.lang.StringIndexOutOfBoundsException

------
Explain Saving Work Item
The Operation is not governed by Process

Have I forgot setting some permissions or what does this mean ?