I tried all of the above but alas.
I eventually upgraded my systeem because cakewalk kept crashing. Got an i7 8GB RAM and SSD drive, it's an old i7 but faster than my old configuration. I also bought a focusrite 2i2 3rd gen so I can be sure the problem isn't firewire related.
I haven't had the problem with the z3ta but now my VIP player is acting up. If I freeze the VIP and unfreeze it, often the synths in the banks of the VIP won't produce any sound anymore. The midi still gets through but no sound. If I unload a synth from a bank and then reload it, it works again.
This is the case for cakewalk and sonar producer X1.
So I'm pretty certain it's me *****ing something up but I can't seem to find what I'm doing wrong.