Well, I went ahead and tried it for a different vhd, one that was just a gigabyte. The converter ran successfully, the machine started up fine in VMPlayer, but then the guest OS (Win XP SP3) gave all kinds of "found new hardware" messages. Evidently, just about everything was different - the network adapter, the display adapter, the IDE, the motherboard, and a bunch of other stuff.
I didn't bother trying to install new drivers
, because I also got a message that since the hardware had changed, I had to activate within three days. There is no way to activate it --- Microsoft says it should run until April, but will not pass Genuine Activation (see here: Download: IE App Compat VHD - Microsoft Download Center - Download Details
So I guess MS put enough bombs in its code that I can't run this with VMWare. Too bad, I like it so much better than Virtual PC.