[Mencent]

You have more parameters in format as %s, %i, %d or %f.

PHP код:

format(query,sizeof(query),"UPDATE accounts SET FactionRank='New Leader',IsLeader='1' WHERE Username='%s'",Player[target][Faction],Player[target][FactionName],Name(target)); 


You have one times %s, but you have three parameters.
I hope you know what I mean.