At least they show there are no hidden snapshots which use the disk space. What I am confused about is that the "Provisioned Size" column doesn't show up. Anyway, a agree with the other posters that it's got to be something in the guest OS which causes the growth.
What's the provisioned size of all the virtual disks on this datastore? And how much free disk space do you currently have on the datastore (please click Refresh to get the current value).
André