I had the same issue as you are having. In fact, I didn't play the game for about 5 months because I thought it was permanently broken. My feeling is the issue is the trainer but I couldn't be sure there was some bugged item or skill or level limit ruining these 2 quests. If you use the skill point+ selection, it ruins at least 2 of the main quests guaranteed (hunters hunted and coming storm).
My recommendations to you are to start a new game. Load the trainer and turn on easy kills only (also of note, if you have IE10 you will need to downgrade to IE9 for the trainer to work; ie10 breaks the authentification method). Use the bow exclusively and don't pick up any items or armor. Also put your skill points into the bow skill line. You should be able to run through these early quests in <1 hour. After that you can experiment and see if the trainer breaks any other quests. I however was too afraid to do so. However, if you use only the bow, don't touch anything I'm sure you can avoid whatever the bug is.
As someone who just beat the game I can say these trainer abilities are safe: gold, exp+, and ability point +. I can safely say the skill+ cheat breaks those 2 quests for some reason.
[Edited by Sunburn74, 4/3/2013 9:35:34 PM]
[Edited by Sunburn74, 4/3/2013 9:36:38 PM]
All times are (GMT -08:00) Pacific Time (US & Canada). Current time is 12:13:04 AM