Whilst I can't comment on the software the forum uses to track IP's

Generally, IP addresses from ISPs, WIFI hotspots etc will be dynamic IPs. As dynamic IP's are asigned by the provider it can be troublesome to locate them. I'm banned from Wikipedia because my provider (BT) has issued a set of dynamic IP's where someone has mischeviously edited (I can register with Wiki but can't edit anonymously)

You may find that dynamic IP's only trace back to your ISP's server or general location. Mine traces back to Newcastle from Low Fell for example, with Sky it used to trace to Leeds

The only way to specifically confirm an IP is a court order.

And of course many people use proxy servers meaning its impossible to trace back