text: what is runtime error, do you want to debug mean? in windows xl, a window pops up and says run time error, do you want to debug?, what do i do? what is that it means that there is a problem with a java application you're using and it's asking you if you want to see if you can find the bug, so as to fix the problem.  if you're not a developer (and my guess is that you're not... otherwise you wouldn't be asking this) then you can turn off the debugging notification.