Back button problem after receiving POST data *RESOLVED*

I've just upgraded to the latest version of PHP. I'm having a little problem with IE expiring pages that have received POST data. What happens is this:

A user completes a form on page 1. The form data is sent to page 2 using POST. Page 2 records the data in session variables for use later and displays another form. The user fills in that form which POSTs its data off to page 3. Now, assume that page 3 realises there is an error with the data from page 2. The user is told of the error and asked to hit their back button and resolve the problem. When they click the back button, they get a page generated by IE saying:

Quote:

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Warning: Page has Expired The page you requested was created using information you submitted in a form. This page is no longer available. As a security precaution, Internet Explorer does not automatically resubmit your information for you.

To resubmit your information and view this Web page, click the Refresh button.

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This didn't happen before I upgraded PHP, therefore I assume it has something to do with the cache/pragma/expiry headers that it sends back to the browser. I understand the reason for doing this, but in this case it is not appropriate - all form data is sent immediately to session variables and is updated with correct data if a form is resubmitted.

I just want the back button to function normally. Any idea how to persuade IE not display this error but instead show the previous page as normal?

OK, I've found a value in the php.ini file that seems to do it: session.cache_limiter