Outlook 2010 and parameters are not valid baloon message

Hi

I seem to be having an issue with updating a calendar entry using Outlook 2010 connected to a Microsoft Exchange 2007 server.

Earlier in the day I amended an entry in one of of my recurring appointments. I added some information and it was fine.

Now when I try to enter something and press save I get a baloon message which says the following:

"Could not complete the operation. one or more parameters are not valid"

Has anyone seen this and can anyone help. I thought it might be that my Outlook needs a tidy up and found some articles which can clean my profile but I think they are all for Outlook 2000/2003 and dont seem to work with the latest version.

Any help would be most appreciated.