simulation problem using programming editor 5.1.1

hi when i run my program in the simulation after a little while it just stops on a if...then gosub... still as if it was running it has all the boxes open and the yellow background is it something to do with my code thanks...

i am not going to put up the symbol names for variables as they shouldnt be needed to figure this out as it will be a code problem.
a quick thing telling what my code does its a game you have two paddles and a ball which you bat around when you miss you get a point first to three wins it is played on a 7x8 dot matrix using a picaxe 28x1 thanks any help will be great ps. it always stops in the pong: heading



thanks alot
danny

its ok all silly me i was just looking at the gosub commands and i a saw that sometimes i have a over 4 gosubs( one within each other) which cannot happen with the picaxe 28x1