I've noticed that alot of the programs listed when downloaded don't open correctly.
If you want to upload a Mac program (at least in 9.1) try it this way. It will save upload time, and should work correctly when downloaded.
Copy the installation file of the program (Ex: Adobe installer)
Drop this copy into Stuff It, compress the file. Upload this file.
If you don't have the installer program, drop the folder containg the program on to Disk copy. Create a image, then drop that image on to Stuff it. Upload the file that is created by Stuff it.