Analogue-sequencer

> I should have mentioned that the tracks are sending on 
> different midi channels to different monotimbral devices.

Ah. Weirder.
 
> The OS is v4, also, it said v3.3 at one stage during the boot 
> up then it says v4.
> 
> But yesterday instead of the 3.3 screen, it went to a screen 
> that says check sum failed followed by four characters and an 
> option to boot or flash. 

The v3.3 refers to the bootloader.
The checksum error means the main program image on the ROM has become
corrupt.
It's possible that might have something to do with the odd behaviour.
Download the firmware in .syx or .mid file format from here:
http://www.sequentix.com/sq_download.htm
...then re-flash the P3 with it.
Just ask if you don't know how to go about sending it the file.

Best regards,
Colin Fraser
Sequentix Music Systems Ltd
http://www.sequentix.com