I'm getting timing problems when sequencing a shaker in sixteenths.

I am using:
Mac G4
Mac OS 9.292
Logic Audiuo 4.8.1,
Pro Tools 5.2.1
MT4,
Digi001
OMS 2.3.8

+ all the latest drivers and software for LA 4.8.1.

I've been using Logic/Pro Tools in this particular incarnation, for two years.

I've just initialised and reinstalled for the 5th time. (hard drive problems).

In Logic, under - Options-Settings-Midi Communication, what out of the following should I have on or off?

'Use Unified Virtual and Classic Engine'
Use OMS if available'
'Use OMS in addition to built in midi driver'

I had another response on the Logic Users Group advising me to take the Unitor driver out of the system-OMS folder.

I've done that, and every conceivable combination of the above options, but the timing issue remains, even when I disable all other track; both midi and audio.

I have been using OMS because I have Reaktor, which requires the IAC facility, but is also giving me trouble. If that further complicates matters, I'll leave it for another time.

As far as I am aware, I have the latest of all softwAre and drivers required for Logic 4.8.1.

What about AMT? I don't have any additional software that I am aware of named AMT.

Really appreciate any help.

Simon Binks