I guess I should have been clearer.
This popup is coming up because your report is not properly establishing a connection to the database you specified in your report. This could be caused by many basic reasons like a few listed below.
- firewall blocking access to SQL
- Improper report configuration
- incorrect user and password
- etc...
The most common reason after upgrading to new equipment that I have seen is the provider was not on the report server needed to connect to the SQL server causing this popup to come up. To test this simply enter the correct information in the window and if keeps coming up then it is most likely the provider. If it works when you enter the correct information then somehow your connection information is not proper in the report itself or the way your updating the report with the connection information.
Note: The native client pack needs to be on the report server(Runtime location).