I've been watching to see which of the guru's would help with this, but haven't seen any action yet.
Don't know if it will help, since I have an active probe, but one thing I would check is the feed rate dro. On my machine sometimes it seems to get into a very low feed rate (like 0.1 ipm) and when it starts the probing I can hear a clicking and it looks like the table is not moving.
Good Luck
Terry