Newbie Question: Undefined Variable Problem

Hi there, Since I'm a newbie to PHP running on an Apache test server (Win2k), I have no idea whether this has been asked before. So I apologize in advance: I have a very simple script that passes a variable from one page to another. However, the recipient page throws an error stating that: Notice: Undefined variable: username in D:\Program Files\Apache Group\Apache2\htdocs\practice\processform.php on line 3 I'm sure this is a setting on the server, since the same script will run just fine on the production server (also Apache). Can anyone shed some light on this? Where do I start looking. I'm sure it has something to do with the script not being interpreted properly (although PHP was installed). Thanks, JB