Coherence works w/2 monitors until I connect my 40" LCD monitor w/diff resolution

I have the following setup:

Mac Pro running (2) NVIDIA GeForce GT 120's for quad video and Parallels Desktop 5 (build 5.0.9370)
(2) Asus 24" HD widescreen LCD monitors connected via DVI
(1) 40" Sony Bravia LCD TV/monitor (on wall) connected via HDMI->Mini Display port

The resolution on the (2) Asus monitors is 1920x1080 and the Sony TV is 1600x900, I believe this is the issue. Coherence runs perfectly fine until I connect the Sony, then my dock goes haywire as does my Windows start menu, until about 10 seconds later Parallels produces an error that the "display config could not be applied".

Is there any manner in which to make this work, like multiple resolution support? How about forcing Parallels to ignore my 3rd monitor? Possible?

Thanks in advance!