Has it worked before OK, when connecting it to a computer via USB?
Have you got the Leapfrog connect program installed in your computer?
This will install the drivers so that your My Own Leaptop will connect via USB
Use a strong light and a magnifying glass to check the USB port to ensure that all the pins are there and that they are straight and parallel with each other.
Also check for any lint etc., which may be in the port enclosure. If there is use a vacuum cleaner to suck it out or if necessary use a wooden toothpick to gently dislodge anything trapped in there.
If the port seems OK perhaps it has become dislodged from the systemboard.
Here's a link to the ifixit Leapfrog My Own Leaptop Keyboard Buttons Replacement Guide which may help in gaining access to the systemboard so that it can be inspected.