HELP! I have a rooted GS4 and my ext sd card are giving me some problems.

My computer can read the card fine, i can write and transfer files over. However, on applications like whatsapp, i am unable to download media. On instagram, i receive an error 'please insert the sd card before using the camera'. On KeepSafe (photo hiding app), I cannot hide any files on my card. When I try to download a file from Chrome on my phone, it comes up with an error 'no sd card'. I have a mounted and formatted card already in place. I have searched thoroughly through forums and have not found a solution. Hope you guys can help !

Thanks

Ext Sd Card NOT recognized by downloaded apps from playstore-screenshot_2013-12-06-19-37-48-1-.jpg