Instead of throwing a useful exception when reading partially or totally corrupt files, app.open() has a nasty habit of popping up annoying error messages (from a scripting POV). There's not a whole lot you can do about it from inside PS. On Windows, you can use AutoHotKey to look for and deal with these error dialogs and there is probably some way of doing the same thing on OS X.
Of course, there may be sekrit codez that I don't know about that work around this problem.
You can use
Thanks for the reply Dominique,
Thanks for your reply xbytor2,
Hopefully someone can help me figure out what Konami-derived codes I need to put in to get things working for me...