Audio problem: When R2-D2, C-3PO and the young-lings crash land on Tatooine, one of the young-lings say "Let's do that again". If you look closely, you'll see that his mouth doesn't match what he is saying. (00:09:45)
Continuity mistake: When Yoda and Asajj Ventress turn their lightsabers on, the lightsabers cast a reflection on the wall. However, when C-3PO and the younglings run past them, the wall shows no reflection cast on the wall. (00:06:45)
Deliberate mistake: When C-3PO, R2-D2 and the younglings are driving through the battle zone, Anakin Skywalker and General Grevious can be seen battling. Later, Darth Vader can be seen on Hoth. This would be impossible due to Anakin Skywalker being Darth Vader. (00:08:50 - 00:12:20)
Audio problem: When the Droidekas start shooting at Yoda and Han, one of them shoot however the sound comes after the shot is fired. (00:16:05)