This is a known Vista issue, and can be resolved as follows:
- Start regedit and browse to HKEY_CURRENT_USER\AppEvents\Schemes\Apps\.Default\CCSelect\.current
- Double click on the defaul value, and clear out the data - it is necessary to hit Delete several times although the field may appear empty.
- Click on OK
More details can be found at http://social.msdn.microsoft.com/Forums/en-US/winforms/thread/d93dd8bb-459a-42c6-8625-79c7a5ba3899