I really don't know. I read the wikipedia on the case after watching the movie, and I was less persuaded of her innocence after reading it.
One of the things that was shocking me while watching the movie (and I started a little late, so maybe they addressed this in the beginning and I missed it) was how cavalier the Indonesian government was with forensic work on the evidence. The wikipedia entry says the Australian government offered to perform DNA testing/fingerprinting, etc., but Corby refused their assistance. That could have been a strategic decision based on feared ramifications of a false positive, but it seems if she had definitely never touched the bag of marijuana, she would have appreciated the assistance.
Setting aside ridiculousness of executing someone for possession of marijuana, what was most shocking to me (speaking as an American and a lawyer) was that they appeared to be basing a potential death-penalty case on a preponderance of the evidence (e.g., more than 50% chance of guilt) standard, rather than the guilty beyond a reasonable doubt (e.g., something like a 95-99% chance of guilt) that we apply here.
BUUUUUT, I also learned that if you go to jail in Indonesia, you usually get one to two months out of jail each year for Christmas break. So there's that.