Well done Mark, glad you got it sorted!!

It is a head banger when you have triple checked everything and yet it is still not playing ball.
It happens to all of us at one time or another.
I remember a few years ago spending ages on a On Screen Display Chip combined with a Pic Chip and had the weirdest errors I have ever seen.
After spending 2 months checking everything and just living with the problem I then suddenly came across a little sentence in the spec sheet stating that if you are running the bus at so in so speed then increase the Crystal caps by 10pf.
So I did this and the thing flew and worked great.

The good thing about having problems like this, is that it forces you to clean up all your code and re-read every part of the manual to get a cure, even though the problem was not in that area in the first place, but all of a sudden you have learn't alot more than if the code just worked the first time around!!

Regards

Sean.