I googled and it said I should have 'kill the bandit leader' but I don't ever remember receiving this quest, or if I did I doubt I did it. I cannot find it in my quests list anyway.
Help?!
I would just start a new character then. Sometimes older characters before the DLC's can be bugged. Right around level 7 you'll receive a letter from the Jarl. Then go speak to him after receiving it and you'll be able to do his favors.
Check in your main and misc quests to see you have anything active concerning the Jarl. If you have anything active, you will not receive another quest from the Jarl until you complete the one that is open. The first one is to get him so "brew." The second one is to kill the bandit leader. Hope this helps.
A bit of clarification: You can do the quest to bring the Jarl Black Briar Mead up to level 8, BUT if you reach level 9, receive the letter and read it the Black Briar quests bugs and won't show up or may show up after a bunch of other quests get done, it is after all buggy.
Once you talk to the Jarl after getting the letter you go kill the target Bandit Boss. Then when you talk tot he Jarl again he will say how he likes you and grants you permission to purchase property. Before exiting this dialog it is highly recommended you talk to the Jarl about any other jobs he might have, if you don't it can bug out and the dialog will not appear. It is this dialog that gives you the option of helping 3 of his people to become thane and shows up in the Miscellaneous quests as Help 0/3 People of Falkreath (may not be exact verbiage).
Additionally, if the DB quest line is an issue just bring lots o' cabbages and gourds to the farmer that is in the town and move up his reputation. You will likely get the Jarl happy enough to speak to you about being a thane and it should count as 1/3 helping of his people. Cheers!
Do you have any kill the bandit, or fetch X quests in your misc objectives?
You can only have one misc quest of each typehttp://www.uesp.net/wiki/Skyrim:Favorshttp://www.uesp.net/wiki/Skyrim:Miscellaneous_Quests
Might be a good idea to clear out your quest list a bit first.