Parfor Problems

Hey
I have got a weird problem... my for loop is working just fine. But whenever i am trying to use parfor, It claims that there is an error in one of the sub-functions (" Index exceed matrix dimensions").

Error using parallel_function (line 598)

Index exceeds matrix dimensions.

Error stack:
run_ode.m at 62
run_sim.m at 9

Error in main (line 26)
parfor j=1:1:n

anyone got any idea?
Thanks!