How do I contact support for Quicktime Pro for Windows?

I'm getting a strange error which even Google doesn't know about. It's "Error -1856: An unknown error has occurred" followed by the filename inside parenthesis. I've tried uninstalling/rebooting and re-installing to no avail. I even tried going through the registry by hand and cleaning up any obvious keys - no dice. Does anyone have any suggestions on how to proceed troubleshooting this??? I need QuickTime to work with Sony Vegas Pro and the Avid codec. Currently it's not even working in stand-alone mode to play files. :-(