Marlene, from my personal experience with the exam, you are right. The errors are with reasons like un-inialized local variables etc...as you mentioned. It won't be silly errors like braces are missing, end quote is missing...etc. Again, that is what I found in the exam.
But that is not an excuse to not to pay attentions to brances, brackets etc...
Marlene, it looks like you are targeting a century (100%)