Post Vars after Server Upgrade

We've got a bunch of web sites that use PHP scripts to allow administrators to edit their pages via HTML forms.

Basically, everything was working fine until the servers upgraded their PHP to 4. Now, POST variables do not show up, whether I use

$POST['name'], $POST["name"], $HTTP_POST_VARS or just the variable straight up (e.g. $name).

However, explicit passing (script.php?name=val), works fine...

Help!

explicit passing is a $GET thing - $POST will have to come from a form with it's method set to "POST".

Is that something to do with it or am i on the wrong track?

If I have to form method set to "post", none of the variables show up in HTTP_POST_VARS.

However, if I add ?var=value to the action of the form, still set to post, it does pick it up...