#2 IE script error messages and "javascript:false" in url bar

[alisa]

At home page, when clicking one of the two links, an IE script error message popps up. I pressed the "Yes" button and got the site, but after several seconds the msg popped up again. pressed again "yes" and this time the url address became "javascript:false" (with the site on), So pressing the "Refresh" button or "Back" button causes the err msg pop-up again. Pressing the "Go" button results in blank page with the word "false"...
OS: WinXP. I've tried this on IE7, Maxthon and Avant browsers - no error message.

[alisa]

IE script error messages

[alisa]

Logged In: YES
user_id=1949982
Originator: YES

The second error msg is different from the first one.

[alisa]

IE Script error msg2

[alisa]

Logged In: YES
user_id=1949982
Originator: YES

File Added: pageTrackerIsNull.JPG

[alisa]

Logged In: YES
user_id=1949982
Originator: YES

In other words (and some addition):
Enter http://sourceforge.net -> IE script error message pops-up ('_gat' is undefined).
Click the Yes button -> got the site but another IE script error message pops-up ('Page Tracker' is null or not an object).
Click the Yes button -> the address in url is changed to the constant address of javascript:false .
And so on every(!) click on link (or sub-link on the SF site) generates those errors, without changing the address.

[alisa]

Logged In: YES
user_id=1949982
Originator: YES

Clicking the "No" buttons generates the same results.

Another site with the same simptoms: walla.com . Every action on email generates those results.
so surfing those sites is inconvenient.