IE6 loose cookies when return to .aspx from .asp web page (works in firefox)

[stillworkingfortheman]

I'm loosing cookies in IE6 (works okay with firefox) with the following
steps...

step 1. set a cookie in one domain, in an .aspx.cs codebehind...
in www.domain.com/subdomain1/page1.aspx
HttpContext.Current.Response.Cookies.domain = "domain.com";
HttpContext.Current.Response.Cookies.Add(cookie);

step 2. Form post (using javascript submit) to an asp page in another
subdomain..www.domain.com/subdomain2/page2.asp

step 3. From www.domain.com/subdomain2/page2.asp, post form values back
to
www.domain.com/subdomain1/page1.aspx

step 4. Try to access cookie from step one but cookie is lost/null, so
following line causes 'object reference not found error'.

string string1 =
HttpContext.Current.Request.Cookies["cookiename"].value;

I already checked to make sure all urls are http, not https. Also,
have IE6 privacy setting to allow session cookies and security setting
for testsite is low.

Does anybody know why this works in firefox, but not IE6?

Also, works in IE if running project locally...
form post from localhost/subdomain1/page1.aspx to
www.domain.com/subdomain1/page2.aspx, then formpost back to
localhost/subdomain1/page1.aspx.

Thanks!