This is from the bug report that relates to your problem.
start of report -If you delete your .Azureus folder or your "Application
Data\Azureus" folder, this bug will go away, BUT you will
also lose all your settings. There is a better way.
Go to that folder and delete ONLY the file
This is the file that stores the Menu labels, and the file
that is corrupted. - end of report
That 'll be you documents & settings/your username/application data/azureus.