It's this error isn't it.
For some reason the installation of SP2 can cause a file called "AUTOEXEC.NT" to be corrupted or deleted. This file is part of the Windows 16-bit subsystem and usually lives in the system32 folder.
What's happening when you get this error is that the setup for that program uses InstallSheild which is a 16-bit program. Since the AUTOEXEC.NT file is missing, it can't run the install program. Not everyone who installs SP2 will have this problem, but we've had several calls and emails about it.
Fortunately there is a backup of the file living on your hard drive.
Double click "My Computer" then your hard drive (probably C drive) and open the "WINDOWS" folder.
Open "SYSTEM32" and see if the "AUTOEXEC.NT" file is in there. Chances are it isn't. If it is, then it's probably corrupt. Arrow up or hit "Back" to return to the main WINDOWS folder.
Go down to "Repair" and double click. You should find "autoexec.nt" and "config.nt" in there. Copy these files (Ctrl+C) then go back to SYSTEM32 and paste them there (Ctrl+V). It will ask you if you want to replace the old one—click "Yes".