This is what I went by.

does it have to say osx in the title?

i found a program with osx and zip in its label, but when i tried to run it, the setup said .exe is it just labeled wrong or is there another way around it?

I had the same issue and just assumed that it was labeled wrong.

to open dos u need windows xp. check boot camp on mac programs then download windows.

I just purchased a new imac and had them transfer all of my files from my old laptop to my new computer. I have been trying to download the OSX version of "SECOND LIFE" for days now and the same thing has been happening to me. It says that the program will not run in DOS mode. I know that I am downloading the correct file for a MAC... so does this mean that they transfered a file from my laptop that ran Windows?
This is all new to me, but this page has been very helpful. Knowing that I am not in this alone helps a lot as well.
I would appreciate any advice!
Thanks: )

I've seen that type of problem before . Unfortunately not sure what causes it. 2nd life runs find on my system. Have you tried setting up a test user account: Setting up a Test Account in OSX (click on link).

Also like happened to me recently, open disk utility from the Utilities folder, see if that particular disk image is shown. If yes, choose the lower image & choose eject. Then choose the main disk image & choose mount. That should fix your problems with luck.