Well - I have sync issues in C5 (and C7):
Try this Grunwaldt:
- Load a new project in C5 and add Z3TA+ with a midi track and controller routed to it.
- Select a factory preset that uses the ARP function - pretty much anything from the Arp or Sequence banks
- Turn off snap and randomly set the transport position
- Play a note....you should either hear nothing, a hung note, or a blippy note...but no arping
- Now press play (hit spacebar)...the arp pattern should begin
- Hit the spacebar to Stop and the preset hangs again
- Turn on snap (to bar) and click the timeline to set the transport cursor
- Viola - the preset plays all arpy again, like it should
I'd be very surprised if you cannot recreate this in Cubase 5. Likely you've always had your project snapped to grid and recorded stuff with the project playing., or you've never dialed in an arped or synced preset.