Please help me if you can.

I have been using Pro 11 for many years now and have downloaded Pro 11 many times due to P.C. crash or hardward updates. I know what to do and have no problems installing it what so ever.

I'm trying to load Sony Vegas Pro 11 64bit into my Laptop but just before the installment is complete, a window pops up telling me that the Download is damaged, I've tried it 3 times now and it stays the same... This is what I see... from A to Z

First I go to vegas account and login-

then - My Software, - products, - Vegas Pro 11.

then when I press download up pops the - Magix Download Center!!!

Then I enter my product Serial Nr...

then - Downloads - installation programm

then the Captcha

and - download start!

then choose 64 or 32 bit then starts the download.

then starts the Microsoft . NET Framework 3.5 SP 1 - install from Sony Vegas.

The installment starts as normal, after 45 secs the loading bar is complete..

then comes a window which says:

DOWNLOAD IS DAMAGED

press OK

Windows from Sony Vegas dissapear... and nothing happens!

Questions: What am I doing wrong? Why do I go to Magix? and what can I do or try next?

I hope someone can assist me?

Thanks and cheers in advance..