Without knowing what the actual problem is, and what you've tried to fix it, it's difficult to suggest solutions.
What happens when you try to download new apps or updates directly on your iPad ? If you are getting an error message then what does it say ? What have you tried to see if it fixes the problem e.g. depending upon what the problem is have you tried closing the App Store app via your iPad's taskbar, and/or done a soft-reset ?