Project executes perfectly in TestComplete but fails in TestExecute

You should check the full name of the button over 2 runs to see if it changes.

Just put a break point where the button is to be clicked.  Using the Object Spy in, TestComplete check the full name of the button. 

Run the test again.  Again when the button is to be clicked in the test, use the Object Spy to check the value of the button.  If it is different to the first run then you would be better off using a Find method.