So who actually owns it at this moment? When you say Server/Billing guy, do you mean the webhost provider or is this a sponsor who currently has it? I doubt you would want to post the traffic stats this site generates in the open here but if you want to provide it, just send it as a Private Message to me. I'd be curious what this site is doing month to month.
Anyways, if you have been in the business for a longer period of time, I am sure you know how to determine if its a good deal or not. Go on your "Gut Feelings" because you can't go wrong with that. The software as you mentioned is In-Link (also called In-Portal) is a good script, and they do offer support, plus I believe they have a support Bulletin board. I still say, contact the makers of that script at In-Portal and ask if they allow license transfers to new owners but as much as I know some people would feel nervous about doing, is confirm that their script can be used for adult usage -- always best to be honest because nothing worse than to have investment and 1000's of hours of hard work be removed because they find out what its been used for and remove the license and tell you to remove their script.
If you cannot use this script for adult, you can still utilize the database and migrate it to a new LL or Directory script (this is a whole different topic on this to choose the best suited one for your needs and there is another thread on this one).
While I think about this, it would probably be best to buy your own license (providing you can use this for an adult site). You will obviously need the admin password to get into the current scripts admin section, or if that doesn't work, if you get access to the database, you should be able to locate it there. But best to get into the admin section to begin your work from there for the take over. Make sure no one else will have access or own anything except you if you take this one over. This includes hosting....unless you have a good relationship with the host provider where this site is now residing, I'd go with one you trust and have experience with.
If you have any concerns or questions, just post them here and everyone at GG will help you out to make sure you are looked after
