I don' think the try blocks would cause the problem that you describe.

Can you post a short sample session with a user? Something like this:
Ask the questions
user enters 1
do work for 1
Ask the questions
user enters 1
do work for 1
Ask the questions
user enters 1
do work for 1
Ask the questions
user enters 2
do work for 2
Ask the questions
user enters 3
do work for 3
Ask the questions
user enters 4
exit loop