If you can install it on a Physical Machine without any issue then I might consider the possibility of it being an issue with VMware however IIRC the only time I've ever seen an issue that could be attributed to VMware was if using Easy Install during Beta Testing and was subsequently fixed.
So if you do a normal install, not use Easy Install, and it fails then you'll need to provide all relevant details however I seriously doubt it will come down to an actual VMware issue since the mechanics of a normal, non-Easy Install, are essentially no different then a physical install and really have nothing to do with VMware other then being done in a Virtual Machine however the Product Key validation mechanism is all Microsoft! 
So what do you expect VMware do about someone else's software in this case if it truly isn't something VMware as any control whatsoever over?