I guess there is something with your settings of security, There might be an option that is asking you an code to unlock the phone which has been enabled and the time limit of the lock must be set to the 120 min interval. Then what you have to do is just go to the settings and just disable the lock. What it will do is not only remove the code lock but also the automatic lock.

Hi Everyone
I have a Samsung Caliber. If I don't use phone for more than two hours. Before I can use it. I have to Enter lock code. The code is last four digits of my phone. I would like to skip this step. I have checked all phone setup can not find where to disable it.
If someone know how to change this setup. Please help me out. Thanks in advance.