Problem with retrieving data

Hi,

I am facing some problem with crystal reports. When I try to open the reports that i have already created, it is showing runtime error message saying

Runtime error!

Program: C:\Program files\Business...

"The application has requested the runtime to terminate in an unusual way

Please contact the applications support team for more information".

I could see the design part.When I try to refresh the data, it is showing "Failed to retrieve data from database".

Can anyone please help me out.