In SME7 the default value of register_globals in php.ini is set to off. If your php code does not use the $_POST array to receive values from the form post, it will not work. You could try setting register_globals on, using a custom template. I expected to do this with a db change, but couldn't get it to work:
mkdir -p /etc/e-smith/templates-custom/etc/php.ini/
cd /etc/e-smith/templates-custom/etc/php.ini/
cp /etc/e-smith/templates/etc/php.ini/40DataHandling .
edit 40DataHandling and change register_globals = off to on
expand-template /etc/php.ini
/etc/rc7.d/S86httpd-e-smith restart
If this works, then you should fix your php code to extract the values from the $_POST array, and reverse the steps to remove the custom-template and reset register_globals to off.