every program I've attempted to download, including .sit, ends up downloaded as a document - when I click on it, it just takes me to Limewire and nothing happens. What am I doing wrong? This only happens with programs, not with audio files.
Amy

The easiest solution is to drag the .sit "document" to the icon of StuffIt Expander. It doesn't care what the resource fork looks like in a compressed file. The .sit will unpack as it usually does.

Thanks - I tried this, I even downloaded the newest version of stuffit expander. Now, when I drag my .sit file there, it unstuffs it become a .dmg file that I then cannot open. Any more suggestions are really appreciated.
Amy

Go to the folder Applications=>Utilities and drag the .dmg file over Disk Copy. It should mount like a disk on the desktop.

I did just that and got a message that the file (file name.dmg) does not have a recognized file type. Hmmm.

In that case it's probably corrupt. Try searching for the file again in Limewire and see if the occurences of the file are the same size. I've sometimes found incomplete compressed files and disk images which, obviously, won't open.

dmg is a disk image file in OS X. It is worthless to you in 9. Look instead for img.