HELP! setup.exe error message

Why do i get this error message whenever i try to install certain programs, such as ACDsee, Acronis True Image, and a couple of other utilities? I've never had this problem before when installing these programs on my other Pc's. This message pops up right when i click on the setup.exe on some programs- not all, but some..

setup.exe - Illegal System DLL Relocation
The system DLL user32.dll was relocated in memory. The application will not run properly. The relocation occurred because the DLL C:\WINDOWS\system32\SHELL32.dll occupied an address range reserved for Windows system DLLs. The vendor supplying the DLL should be contacted for a new DLL.

Any help or suggestions would be greatly appreciated. thanks

thanks alot for the quick reply. ran Microsoft updates and tried installing programs again and worked out fine. thanks again!