I just noticed that the clock on my guest Windows XP system was running way too fast on my host Ubuntu Gutsy system. I had also noticed that double clicking seemed really difficult and there were a few anomalies with sound.
A bit of Googling turned up this tip from the VMware knowledge base. So to fix things I added these lines to the bottom of /etc/vmware/config.
host.cpukHz = 3060000 host.noTSC = TRUE ptsc.noTSC = TRUE
Now the clock and lots of other things are better.