Task Scheduler

I mostly run php on *nix machines so not sure about this.

Normally php scripts are run by the web-server when someone requests a page with some php in it.

In your Server 2008 set-up your default action for .php may be set to another action (e.g. 'open file in editor') rather than 'run script using php.exe'

You have to call up the php interpreter and use your actual script as a command line parameter.

Something like

php.exe d:\InetPub\tools\something\build.php

You may also be able to achieve the same effect by associating .php files with the correct program

This is the issue described in KB2617046: if you disable and then enable a scheduled task, duplicate triggers are created. The task properties still shows only one trigger, but you can see that the task is triggered multiple times simultaneously in the task history.

There is a hotfix available from Microsoft. The hotfix says it is for Vista, but it works on Server 2008 SP2. After applying the hotfix, you have to disable and then re-enable the trigger on your task (closing the trigger properties window in between to apply the changes) in order to get rid of the duplicates.