cant install due to nsis error

Hi,

this is what I get when I try both ver11 and v12rc2. windows version


Installer integrity check has failed. Common causes include
incomplete download and damaged media. Contact the
installer's author to obtain a new copy.

More information at:
http://nsis.sf.net/NSIS_Error

I tried to run with the /NCRC switch and it bombed out with a corrupt file error.

Any ideas (I have downloaded via FF and IE) same error.