There is another thread about this problem (an error has occured C2-13688-6) on Playstation allstars battle royal.
I have found a solution, but the moderators have closed the thread (Click Here). So if you want then please state this solution in the other thread (it is ranked in google)
-TESTED IN BELGIUM-
-Go to your PS Vita Settings
-Go to Playstation network.
-Go to your Account details.
-And change your language to French.
-Save your settings.
-Go back to your game
NOTE: Your PSN account menu will now be in French, if you change it to Dutch again, then it will give you the error again. So this is only atemporarily solution.
NOTE2: I'm not sure if you can change the language if you are from The Netherlands (I'm from Belgium).
Then it should work fine!