[Ballbarian]

You should be able to find comdlg32.ocx in your windows\system32 directory. It may be that you just need to re-register it by typing "regsvr32 comdlg32.ocx" from the command line in the system32 directory.

In case you are not familiar with the command line I will include more detail below.
You can get a command line from:
Start->Programs->Accessories->Command Prompt.

You should get a window with a black background and a blinking cursor. Type cd\ to take you back to root and then type cd windows\system32 to switch to the system directory.

Now type:
regsvr32 comdlg32.ocx

Then:
Exit

This will re-register the control and then exit command prompt.

Hope that helps.