Crystal Reports and OLEDB

We have had numerous occasions when Crystal Reports inside LRS have all of a sudden started prompting for an OLEDB username and password. We can input the porper username and password into the report and it will work just fine for that one time, but will keeep asking for the username and password each and every time that it's run. We even had some report instances that were run overnight in our history today that would prompt for the OLEDB username and pasword. Does anyone know how LRS uses the OLEDB username and password once the report is loaded into LRS. Does LRS cache this information somewhere? Does anyone have any idea why this may be happening?