Import ZASM -> Crash

[ZoriaRPG]

ZQuest will crash if when the user imports a ZASM script, they enter an invalid filename in the file lister.



Note than I import ZASM for one of three main reasons:

1. When a quester provides a quest in which they need me to add an ffc, but they do not apply, or they do not have all of the ZScript files.
2. When recompiling requires rearranging headers, and importing precompiled ZASM is easier.
3. When I wish to 'idiot-proof' adding a script; usually ffcs.