I’m not the guy who writes the code, but I’m usually the guy who has to answer the halts, and few things on a green screen are quite as frustrating as this: An array index is out of range. There follow several, usually four, options, none of them good. I lean towards D, which is basically C (cancel program) plus spool a memory dump.
Applications written around arrays have caused much destruction. I once had a matrix mechanics job, a twelve-hour program that ran on a supercomputer, fail in the ninth hour because of an array problem. The great continent-wide communications crash of a decade ago was caused by a mis-defined array. Two major stock market recording debacles occurred because an array was undersized — the same array in both cases, ironically enough.
Then again, a lot of this is legacy code that we don’t have time to rewrite. I swear, there are still bits of junk from the 1990s being called here in 2016.
This is probably not the time to note that we have one office subsystem running on a Windows XP box.