(for the following, I’m assuming you have a share-hosting account)
You don’t mention making the the post-commit file executable after removing the .tmpl extension – that could be the cause of the immediate error.
Probably the “/bin/php” will cause an error, since on DH the php binary is under /usr/local/. The default php binary is PHP4, but I’m guessing you’ll need PHP5, so use: /usr/local/php5/bin/php
The path to notify.php would probably be something like:
However, the WhompBox post suggests using $REPOS to locate notify.php, so the following php call should work:
/usr/local/php5/bin/php $REPOS/hooks/notify.php $REPOS $REV
I hope that helps; let us know if you succeed.