See how do I open blank "limewire document" All you need to do is drag & drop a healthy file into Mac Army Knife, then make a note of what it says the creator & type are. Then drag the blank document of same type into Mac Army Knife & change those 2 details to what the healthy one said.

eg: ----------------> Type .......... Creator

mp3 ---------------> MPG3 ......... hook (hook is iTunes)
sit -----------------> sit4 ............ sit!
simpletext -------> TEXT ............ttxt
jpeg image -------> JPEG .......... ogle (ogle is Quicktime/Picture viewer file)
Divx --------------> VfW ............ TVOD
.mov file ----------> MPG * ........ TVOD

* should be very wary about changing the type for video files!!!

Remember that in OS 8 or 9 that the maximum length of a filename is 32 characters. Both Mac OS X & windows 2k & later allow longer filenames. OS 8-9 will shorten the name & thus cutting out the extension. So if you see such a file that looks like the name has been shortened, shorten the name. Also add back the extension. eg: let it.mp3 (instead of - let it have its own way to dAEHEHBHSI%#)