when I get to step  to unzip the file to C:\directory

I get an  error , in a message box  'winrar diagnostic messages'

it shows the path of my downloaded zip file

C:\document and setting\mydocuments\dot_net_nuke_04(1).09.01_install zip: and  message "The archive is eithier in unknown format or damaged"

what could this be?

I have tried numerous times now, to download, even previous versions  I was able to download the documentation file for 4.9.1, but source and install , no luck...

I get a message , when trying to unzip the files , with winzip or  winrar

win-zip: cannot open file it does not appear to be a valid archive, if you downloaded this file, try download again...

what is the cause of this?

I really wanted to use this kit, I am following the steps to download, the unzipping of file to the C:\directory is where im stuck.
It wont get me past that stage.   

Suggest your clear out your browser cache and cookies. Also if you are going through a company proxy you might need to clear the cache from there.