I recognize these symptoms...
The only workaround I came up with was....
Start Powerpoint BEFORE starting Zionworx.
In fact, I have Powerpoint as a shortcut in the Windows Start menu (Startup folder), so that other people don't have problems.
I'm running XP Home, Powerpoint 2007, Zionworx 2.65.
Everything works fine apart from this Powerpoint quirk.