Try a different browser, I had no issues using Firefox do download.
I'm on Mac too. I don't know why you think you are 'trapped' using Safari.
I AM HAVING THE SAME PROBLEM BUT MY PC IS A TOSHIBA 64X IT WONT ALLOW ME TO DOWNLOAD!
All the browsers repeatedly failed to download from mega.... and when i say failed... i mean when the download went live..... it was several hours of even isntalling chrome.. opera.. and safari just for the sake of attempting to get a bloody download to work somewhat, and it was fruitless.Once a mediafire upload was made available, i had it in 5 minutes no problems.MEGA has always been a hunk of crap.Post Mergehttp://bit.ly/1Dy4J1FDownload from that.
Do check my thread at http://forum.legendsofequestria.com/index.php?topic=14289.0 if you haven't done so, it might help! Also, I had no issues downloading from MEGA using the latest version of Safari. I just left the tab untouched till 99%, then carefully clicked anywhere in the webpage again, waiting a few seconds for the "save to your computer" dialog to appear.
The file downloaded from MEGA should be a .zip file. Double click it, and Archive Utility should automatically extract the file contents for you. Once that's done, you should see an icon on your screen called LoE. That's the file you have to open.