I guess, the problem becaz of your default privacy settings, when u install IE6. Here are some work-arounds from MS site:


1) Privacy preferences that you specify on the Privacy tab in Internet options using the slider, the Advanced Privacy Settings dialog box (by clicking the Advanced button), or the Per Site Privacy Actions dialog box (by clicking the Edit button) affect only the Internet zone.
http://support.microsoft.com/default...;EN-US;q282846


2) Explorer 6 implements the P3Pv1 Compact Policy specification to gather metadata about the intended use of cookie information for the Web site.
http://support.microsoft.com/default...;EN-US;q290294
Description of the Platform for Privacy Preferences (P3P) Project


3) The Compact policy information is used in combination with user preferences to determine whether Internet Explorer 6 will accept or block cookies from the Web site.
http://support.microsoft.com/default...;EN-US;q290333
Default Privacy Settings for Internet Explorer 6
http://support.microsoft.com/default...;EN-US;q293222


4) Some Web Site Services Do Not Work After You Upgrade to Internet Explorer 6

Some Web site services may not work properly after you upgrade to any of the versions of Internet Explorer listed at the beginning of this article. The Web site may suggest that you need to enable cookies or upgrade your browser to one that supports Java, frames, or other technology that is supported by Internet Explorer 6.
For example, when you attempt to log on to, or use, a secure banking Web site, you may be prompted to upgrade to a compatible browser or a different version of the same browser.
http://support.microsoft.com/default...;EN-US;q302708



For more info: pls go thru this link:
http://www.security-forums.com/forum...pic.php?t=1060