[nhawk]

Editing the source code for vB is never a good idea. Doing that means you have to edit the code every time you upgrade.

Try this...

Go to ACP->Plugins & Products->Plugin Manager. Scroll down to the bottom and click 'Add New Plugin'.

On the page that follows enter this info...

Product: vBulletin
Hook Location: login_strikes
Title: Admin Failed Login Email
Execution Order: 5

Code...

if ($strikes_user['strikes'] >= 5 && $message)
{
	vbmail('yourname@youremail.com', $subject, $message, true);
}