Quite often I get the above message when loading 9.0c 64bit on my Win7 64bit system (i7-920, 12Gb RAM, clean install).
I have two Spectraview 2190 DVI monitors connected to an ATI Radeon HD5770 graphics card.
Vegas just sits there and can't even be killed off in Task Manager.
Only solution is to reboot the PC and try again.
Does the "external monitoring" refer to the 2nd monitor, or some other device.
Any help or suggestions would be most welcome.