I've been having a major VMWare problem on my Fedora 8 x64 workstation. Creating a new VM was no problem. Whenever I tried to power it on, however, my entire system would lock. Being the demanding, unreasonable jerk that I am, I wasn't willing to accept this behaviour ;-)
I found this post (I was amused watching the two posters bicker over 64 bit VMWare) which pointed me in the right direction. I unloaded the kvm_intel and kvm modules. After that, my vm powered on like a champ!
So, if VMWare Workstation 6 is crashing your linux box, see if running these commands helps:
sudo rmmod kvm_intel
sudo rmmod kvm_amd
sudo rmmod kvm
P.S. I've added learning about KVM to my homework list. This link is a start.