I think Brent has mentioned before that it's a "server issue". He seems to have customised the vBulletin software a fair bit, but it's hard to say whether the forum software is at fault, or it could be server load, database issues, etc.
For anyone interested, you can find all sorts of info about a web domain using freely available tools on the internet.
Using "whois" we can see who clubcobra.com is registered to...
Whois Lookup | Domain Availability - Registration Information
builtwith.com can show us what the site is built with...
clubcobra.com Technology Profile