avast 5 free does not install

hi all,
I recently tried to install avast 5 free antivirus on my laptop running windows 7(clean install) but it does not install. It gives an error message saying “An error 1006 (000005EE) has occurred. Last performed action was: opening the self extract archive”

I can’t understand why this might be happening ??? i had installed avast on windows 7 earlier and it worked fine, but now after I reinstalled win7 and tried installing avast this happened :-[

I’ve been using avast ever since I had a laptop and don’t wanna switch to any other AV program :cry:
HELP PLEASE!!!