ntdll.dll error

Love the product first and foremost!

I have had several problems loading versions greater than 3.7 on my Window XP Professional machine. I installed the latest version 4.2.2 and it works the day I install it. The next day, I get a windows error when I double click and it sends Windows standard Error window with the message that the problem is with ntdll.dll. I then have to revert back to the 3.7 installation for it to work fine beyond the initial installation day.

Any ideas? It doesn't appear to be SuperEditor perse, but its attempt to open or use the dll file.