In LV6 you can go to Browse>>Breakpoints in the menu and it will display a dialog with a list of all breakpoints in any currently open vis. You can also use the Highlight Execution button to follow the flow and find out exactly where it is stopping. If it hangs on a sub-vi or function then you need to figure out why that sub-vi/function can't complete. This could be for a few reasons, is it trying to talk to a resource that isn't available?. Do you have a loop in a sub-vi that never finishes? Maybe there is a long delay somewhere that you just aren't waiting long enough for...
If this doesn't help then give us some more specifics as to where it stops, or even post the part you are having trouble with.
Brian
