If you just downloaded the program, there may have been an error during the download. If you've been using the program successfully, and this just came up, you may have had a disk error (ie. power outage while Windows was still running, or whatever).
Either way it sounds like a corrupted PVD installation. Re-install from a "good" source will ensure it's not a program issue.
Please help! After starting the program, I found this note:
internal Firebird consistency check (cannot find record fragment (248), file: dpm.cpp line: 1246) Unsuccessful execution caused by a system error that precludes successful execution of subsequent statements Error Code: 13
Then open an existing file that is empty. The new file can not be loaded and closing the show:
madExcept 3.0 · non-commercial edition internal Firebird consistency check (can't continue after bugcheck) Unsuccessful execution caused by a system error that precludes successful execution of subsequent statements Error Code: 13.