Can somebody with too much time on their hands help me troubleshoot something?

http://www.heavybombers.com/.../gossamer/gforum.cgi

Feel free to test post as it's not linked into my main site and won't be until after more testing.

Example post: http://www.heavybombers.com/...r/gforum.cgi?post=8;

Click on its attachment which generates this URL result:
http://www.heavybombers.com/...chment;postatt_id=1;

For some reason, it's inserting the "/filename.jpg", with it extracted the URL is correct.

i.e, http://www.heavybombers.com/...chment;postatt_id=1; does link correctly to the file.

I've done something wrong somewhere right? I looked at my Attachments setup options but didn't spot anything obvious. Everything else seems to be working like a champ.

Dazed and confused,