Wierd 404's Spam attack or mis-configuration?

[True2Life]

Hi All,

Not sure this is exactly Apache related but let me explain.

I setup a 404.php page with a little code that sends me an email stating the link the user tried to access, their resolved IP and the referred link.

This weekend I got 6,000

example.
=========================
Sat Mar 29 2008 5:57:43 pm GMT

83.40.214.162 [162.Red-83-40-214.dynamicIP.rima-tde.net.] tried to load www.true2life.co.uk/portfolio/roomconfi ... php?PHPSES

User Agent = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET)
=========================

The other 5,999 are similiar but have valid but different pages at the end of the URL and either more or less /portfolio/ duplicated folders in the middle of the url.

They are direct links as far as I can tell.

The problem isn't the fact I get lots of these emails but more to the "why". and could this possibly be a server configuration issue somewhere?

Any help would be greatly appreciated.

Thanks
Geoff