Yuk! One of those ugly problems almost impossible to fix in an organised way but I suspect that the scanner drivers have overwritten a MS or Adobe file with one of the wrong date or version.
Some old Adobe stuff was very flaky on the IBM PC. It was, after all intended for the Mac.
Check the date of that MFC42.DLL in Windows\system. Is it consistent with the rest of the system files? If not it may be worth finding a copy that is.
On my 98SE machine nearly all files in that directory (incl MFC42.dll) are dated 23 Apr 99 at 22.22.
My MFC42.DLL is version 6.00.8447 (it also claimed to be 6.0.300) and consists of 995,383 bytes.
I can e-mail it if you want it but to install it you may have to start up in "Safe Mode" to be able to over-write the existing file.