VMware Server needs exactly two kernel modules running on the host system (there are separate modules for guest systems). These are the vmmon and the vmnet modules. Unfortunately, the vmmon and vmnet packages included in the VMware server distribution package don’t compile with the newest kernels. When I upgraded my laptop to Gutsy Gibbon a few weeks ago, I forgot to check if VMware server supports the new kernel. And, of course, it doesn’t yet. But luckily I found the vmware-any-any package, a patched version of the host kernel modules that works with newer kernel versions.