This solution worked for me:
1. Go to the start menu, and search for the "cmd" function.
2. Drag the downloaded HON client onto the black box (the directory of the HON client will appear).
3. Press space and type /NCRC.
The above should allow you to bypass the NSIS error!
*Taken from
http://www.ehow.com/how_5541530_fix-nsis-error.html