ERROR: DLL could not be opened

After I run the Registry Cleaner and I reboot, as soon as the desktop opens, I get a small error message that says:

ERROR

DLL could not be opened.

There is no error code or any other information that would indicate what DLL file or where it is located.

I have used the Registry Cleaner hundreds of times before and never had a problem. This is being used on my new Dell laptop using Windows XP Pro.

I have run several spyware and anti virus programs and the machine is clean (it's new).

Any help would be greatly appreciated. Thank you!