Crystal Reports Database Login for Report Incomplete or Incorrect

Message

   Hello,

We use Business Objects XI Release 2 with Crystal Reports and within the InfoView web service for various reports we get an intermittent issue with viewing certain reports. The message we get with some reports is as follows:

CrystalReportViewer 
The database logon information for this report is either incomplete or incorrect.
Unable to retrieve Object.
The database logon information for this report is either incomplete or incorrect. 

Now, the problem is that this report then works after a few weeks and then stops work for a while.

What could be the problem?

Anything I can provide that will help?

Thanks.

Regards,
Chris K.