I am managing a script which should run not less than half an hour however the script stops after thirty seconds...

I am unsure why because it done other server before.

Can there be somewhere I have to check?

Make use of this:

ini_set('max_execution_time', 0);

You may also edit php.ini:

max_execution_time = 60; //Maximum execution time of each script, in seconds
max_input_time = 60; //Maximum amount of time each script may spend parsing request data

Hope this can help.

You will need to tweak the max_execution_time value within the php.ini file. Bear in mind that installations of PHP frequently have a php.ini apply for the server and something for that command line interpreter. Make certain that you simply edit the correct one.