I was having this problem for a couple of days. Wasted many hours trying to figure out what the problem was.
Apparently, the glibc libraries that come with CentOS 5.4 cause the vmware-hostd process to crash. It's a known issue. You have to downgrade your glibc libraries to those from CentOS 5.3.
Here are the details of how I fixed the problem, along with a link to the bug as reported on a the bugs.CentOS.org site.