You should be able to enter the line number you want to run from, hit run from here, cycle start. You should see a pop up saying mach wants to make a prep move. Accept the move, hit cycle start. It is assuming it has run the code to this point allready so if you were running a roughing pass in the code before the point you started at and you just skipped it by run from herre, that would make a mess.
Hope this helps some,
Brett