Error message in Quicktime, Windows Media and Mozilla

Hey there,
Please help me out. I keep get an error dialog boxes in several programs in my computer.
These include Windows Media Center Player, Windows Media Player, Quicktime Player and even Mozilla Firefox.
I have reinstalled all programs, but the error message still appears. What does this mean?
Can anyone help me out here? I'm desperate for answers. Any help would be appreciated.
Thanks in advance!
Here is the screenshot of the error message:

Message 1:
Ehshell.exe – Common Language Runtime Debugging Services
Application has generated an exception that could not be handled. Process id=0x1350 (4944), Thread id=0x7c8 (1992).
Click OK to terminate the application.
Click CANCEL to debug the application.
OK Cancel
Message 2:
Ehshell.exe – Unable To Locate Component
This application has failed to start because DBGHELP.dll was not found. Re-installing the application may fix this problem.
OK
