The problem occurs with IIS 4 (NT 4, All SP) using the CGI version of PHP 4.2.1. Whenever a form is submitted using the post method, the last POST variable submitted loses its last character of content.

The below code reproduces the problem:

<?php
	echo "
	<form method=\"post\" action=\"$PHP_SELF\">
		<input type=\"text\" name=\"textOne\" value=\"Test 123\">		
		<input type=\"text\" name=\"textTwo\" value=\"Test 123\">		
		<input type=\"text\" name=\"textThree\" value=\"Test 123\">		
		<input type=\"submit\" name=\"SubmitButton\" value=\"Test Post Bug\">
	</form>";

	phpinfo();

?>

In this casee, $_POST['textOne'] would return "Test 123", $_POST['textTwo'] would return "Test 123", and $_POST['textThree'] would return "Test 12" -- missing the final 3.

The same code on IIS 5 doesn't produce the problem however I have run older PHP (4.0.6?) on NT 4 about 4-6months back without this problem. Not sure if this MSKB article is relevant: http://support.microsoft.com/default.aspx?scid=kb;en-us;q203298

BTW Register globals is on.