Mantis application warning #2702 is just it saying there's a session mismatch between the user and the server. I can't find anything really going into detail on, besides the fact that it's been fixed as a bug in multiple versions, to include a bug fixing it for the version BM runs (which is old as dirt, for the record).
As for the bug itself, in regards to the game...
select P.ID from Players P left join Tournaments T on P.ID=T.Maker where P.active='yes' and P.ID!=5070 and P.Status in ('tournament','aftertour') and P.Location= or (T.ID is not NULL and P.ID!=5070 and P.active='yes') ORDER BY CharacterName ASC
"P.Location= or" is missing the thing it should be equal to, which means a variable isn't getting passed, possibly because the player id in question doesn't actually have a location? I'm not sure what player id means in relation to BM, though. I'd probably need a chart to wrap my head around how it works sometimes.