I found a bug that prevents OpenOffice (v3.1.0) from saving a document after CCleaner has been run.
Steps to reproduce the problem:
Open a file in OpenOffice (I think you have to change something for the bug to arise).
Run CCleaner including OpenOffice-files (The problem seems to be the cleaning of "C:\Users\[username]\AppData\Roaming\OpenOffice.org\3\user\registry\data\org\openoffice\Office\Histories.xcu").
Try to save the file - you won't be able to. OpenOffice will show an error-message.
Maybe you can develop a workaround for this problem?