You'll probably need my detokenize Axiom to do anything useful with the input command. Off the top of my head, I'm not certain why it would crash, but I can think of a few possible reasons.

It could be that you're parsing the data returned by input incorrectly. It's tokenized, in case you didn't know. Tokens are explained elsewhere, but suffice it say, you can't send the result of input directly to Output or Disp, and it's unwise to pass the result to GetCalc( without validating that the user typed a valid name.

It could also be due to memory allocation issues. input is special in that it allocates a special temporary variable to hold the text the user types in. A temporary variable is just a regular file (like Axe files, programs, Strings, Pics, &c.) that is automatically deleted when your program ends. It's entirely possible to run out of memory by calling input multiple times, so the detokenize Axiom has a CleanAll() command that frees all of the temporary memory input allocates.

If you create, resize, or delete anything after calling input, the pointer to the temporary variable becomes invalid (the OS moves the variable) and you have no way of getting a new, valid pointer. You can do it in assembly, but it would be a bit of a pain. (Of course, in assembly, you'd already know the same of the temporary variable, so getting a new pointer to it would be easy. I wish Runer would add an option in Axe to get the VAT pointer to files; it would have reduced the excessive amount of assembly code embedded in its source.)

You indeed do not really need input for getting input into your program. You can also write your own input routine.
Not that I ever needed to, though.

Yep, the 83+ and 84+ series are largely the same, and ASM programs for the 83+ run on the 84+.

Wow thanks everyone. It's weird for me to get good responses from people, I guess i'm just used to crappy forums.

Perfect, because i'm probably going to need lots of it.