Facebook like box widget can't be added

Greetings.   I have tried to add 3 different plug ins to the simple catch theme and neither of them work. At all in fact. Is there an incompatibility issue? I have tried adding a text widget into the sidebar, and none of the plug ins worked. I have tried looking for the answer on youtube and it did not work. So, perhaps someone on this board can shine a light on my problem for me.