TWD won't install on Mac

[jenmcm76]

I'm trying to install my purchased copy of the full 'The Walking Dead' game on my MacBook Pro but the program won't even install. I downloaded WalkingDead100_v3.dmg from https://www.telltalegames.com/mytelltale/purchases, and the download appears to have completed successfully. When I click on the .dmg file, I get a pop-up stating that:

The following disk images couldn't be opened
Image Reason
WalkingDead100_v3.dmg not recognized

That's it - I'm dead in the water.

I'm running Mac OS X Lion, 10.7.5, and yes I already disabled Gatekeeper as suggested by DjNDB.

Any suggestions?

[DjNDB]

One possible reason is that WalkingDead100_v3.dmg got corrupted somehow.
Please try deleting WalkingDead100_v3.dmg and downloading it again.

If the same thing happens, please post the checksum of the file as described below, so we know for sure if it's corrupted. It is assumed that WalkingDead100_v3.dmg is in your Downloads folder.

Open a terminal (e.g. by typing terminal into spotlight).
Run md5 by copying the command line below into the terminal and pressing enter:

md5 Downloads/WalkingDead100_v3.dmg | pbcopy

Now start a new reply to this post, and paste the clipboard into it, by pressing Command + V.

[jenmcm76]

I deleted and re-downloaded several times, finally trying the download through Safari instead of Mozilla. For some reason, that seemed to work. I was able to get install the game, and get to the start menu, anyway.

Thank you for your suggestions - fingers crossed that it runs smoothly after this.