Anji, I've completed all the puzzles with time travel with no problems.
I've also learnt that you should wait when until you have crops to set your clock back.
What you need to do is, make sure you no one is working on farming and are all busy. Pause the game and quit.
Set your clock back. Open game and unpause.
When I did this everything was honkey dory

Just make sure you do follow my simple tips for safe time travel if you do time travel and things should be ok. (The link is somewhere on this thread)
Remember:
Setting your computer clock back and forwards can muck up other programmes such as Anti Virus ones majorally!!!
Do not time travel if it's not your computer or if you're under 18 and it'll will make your parents angry.
LDW do NOT recommend time travel at all and it may interfere with the game and cause problems for them. So please try to avoid time travel.
If there are problems and you have time travelled, it's you fault and do not whinge, whine, moan or complain.
While others consider Time Travel cheating or that it takes the enjoyment out of the game, I disagree.
I also find if you do it safely like I mentioned (although there is no safe way really kids) then it only enhances the games during those boring waits for tech points.
Good luck and best wishes
