Two unconfirmed reports:
Brian McCarty writes that the new Timbuktu Pro 4.0 update would not load when Conflict Catcher 4 was installed. It would work fine when he switched to Extensions Manager.
Update: Steve Parker is running Timbuktu Pro 4.0 and CC 4.0.3 without this problem. Monte Harvey similarly reports no problems with Timbuktu of any sort.
Lee Neuman claims that Timbuktu Pro 4.0 does not properly display VirtualPC screens. [Maybe it is expecting a bit too much of Timbuktu to do this well.]