Hi shaycourtney1,
1. When do you receive the error message?
2. Have you made any recent changes on the computer?
Msimg32.dllis a system file in Windows vista.
If you are getting the message when opening any program or during startupI would suggest that you run SFC scan on the computer which would scan for corrupt system files on the computer and replace them.
The scan may take some time, so be patient. Windows will repair any corrupted or missing files that it finds. If information from the installation CD is needed to repair the problem, you may be prompted to insert your Windows Vista installation disk.
For more information refer the below link.
How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7
**http://support.microsoft.com/kb/929833**
Hope this helps!
Halima S - Microsoft Support.
Visit our Microsoft Answers Feedback Forum and let us know what you think.