I am using Logic Express 6 on my G5 with a audiophile 24.96 soundcard and Roland XP30 synth. I have always used a template environment for the XP30 which is good but when I select Midi Tr. 16 on the arrange window it triggers my XP30 from perform/part mode to Layer mode which I dont want.

This only happens on tr 16. How can I change this or what settings should I be checking on this track. I have checked that all the program numbers and everything else matches with the other tracks (on left hand side box in arrange and environment)

Any advice would be great!

Just a tentative suggestion - check the assignment of Track 16. I have Logic Express 6 and the Autoload default for 16 is usually Klopfgeist - the posh clicktrack.
This may be affecting something or other.

(Hey, I'm a bassist, not a computer nerd!)