check your dump partition:
But it depends what crashed that you want to look at. a VM would dump in the vmx directory. The hostd and vpxa both crash in their respective directories either /var/log/vmware or /var/log/vmware/vpx. ESX crashes I typically look at after the vm-support has been run and in that case it is copied from the dump partition to the /root directory. However, the easiest way to see what happened if you are lucky the /var/log/vmkernel file (or vmkernel.1 if its been rolled over) will show the stack trace and some possibly helpfull messages to indicate what happened.
Hope that helps.