Loss of viewstate on 2000, not xp. Possibly iframe related

[ChrisC]

I have my aspx page that contains an iframe. when I navigate the iframe
to other places by changing the src attribute on a button click from
the .net portion of the page I lose all viewstate information - drop
downs revert to default and even more bizarrely, any further attempt to
change them has the same result - it enters code in the !ispostback
section of page load, which is odd.

More complete explanation of app -
a single aspx page with a number of drop downs to select various
criteria for generating a report. These drop downs have autopostback
set as the other dropdowns are dependent upon their content. There is a
'run report' button that sets the src attribute to a reporting services
url with the parameters from the drop downs.

This problem only occurs on 2000, not xp. Versions are both up to date,
although the xp one has the same version number but suffixed with a
xpsp2.extrastuff..... section. The xp machine does not have sp2
installed.

[ChrisC]

Looks to be a server issue - hosting it off my local development
machine 2k + xp both seem to work fine with it... bah.