Today I had a problem with Telerik Grid showing a databound column on the test server, in that crazy US format (no offence to Dave!) 'mm-dd-yyyy' rather than they far more logical format 'dd-mm-yyyy'. This was not the case on the Production server or when running locally on a development PC. Logging on to the server and manually setting the region to "Australia" did not work.
The solution is to check the user account under which the application is running under IIS; then logon to the server using this account and changing the region. After that you'll need to do an IIS reset and all should be well.