For the leak (it's like a hole in your map) you can use the leak check. Open your map in BSP and choose File -> Leak Check -> Load Leak File (alt. Load (.pts)). Follow the line, find the hole in your map and close it.
For the lights you can just use some of the light textures. It's one of the most easy ways to add lights for beginners.
Finally make sure you are running a full export (final compile) without any warnings, errors or other problems.
It would be very helpful for you, if you would read the sticky topics in the mapping board. You can also asked for things you don't find there or you don't understand.