The graffiti about town is rolled randomly. You might not have found the graffitti that is was a good hint. "Drakthar is dead, Long live Draktha" though is written on the wall at the bottom of the stairs immediately when you enter. Either your DM missed it or your PCs don't read goblin. ".
Thankfully one of my group did read goblin - this should be one of the recommendations at the start of the adventure path so that you can make sure that one of them can do this....
Once you are 'in the dungeon' you will find the graffiti everywhere, so they will be able to read all of it at once....
Actually, what got me into a LOT of problems were the 'cursed' items in Jazadrune (spelling)....
Identify has changed DRAMATICALLY in 3.5.... How did you allow your characters to discover which items were cursed?