How can I disable the "No symbols found" messages that show on the debug output window when I debug my program?

Unfortunately, you can't configure most of what shows on the debug output window, including the dll load messages.

This, however, is not an error message. It simply informs you that the IDE found no debug symbols for the loaded DLL. One good way to get rid of the "error" is to actually install the Windows NT/2000 debug symbols on your CD, which you can download from the Microsoft website, or from the CD marked "Customer Diagnostic and Support Tools" on your MSDN subscription. As an added benefit, you'll have a much easier time debugging complex problems.