Message: 'null' is null or not an object

I am trying to launch my joomla 1.5 site next week and I am getting the following error on all of my pages (www.jazzrevue.com):

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Timestamp: Tue, 10 May 2011 04:36:23 UTC


Message: 'null' is null or not an object
Line: 169
Char: 3
Code: 0
URI: http://www.jazzrevue.com/templates/gk_m ... .script.js

I seem to be getting many server errors and I am not sure if this is causing the server error.

Line 169 is: if($('popup_register').getElement('.gk_popup_close')){

I figured out that this error was caused when I turned off the gk_register module. i turned this off because I was using the K2 registration. I did this because I need the registered visitors to have a K2 default user status. How can I use the gk_registration and automatically set a K2 user. I set this up in the k2 parameters but it did not work.

Any ideas?