[alanesq]

From what I understand of longbows and I suspect this is true of any wooden bow?
If you catch a problem early it can be fixed but it soon becomes a very big problem if you carry on using it (a phrase I once heard used on an open university program seems to sum up what tends to happen with wooden bows "a sudden and catastrophic failure")
So I would return it to the place you got it from ASAP

As for aiming the trick seems to be to first work on getting a decent group even if its not where you expected it to be - until you can get a decent group you will never manage to get a decent aim (as each arrow will go to a random place anyway)