Samsung Tablet Pro Model GT-P7500

I purchased this device a year ago and am trying to download apps from play store and market store, it does not download,i always get a notification of some error as follows. Error Retrieving from server {DF-RPC-01}
I need Your Help It Gurus/Genius asap.A screen Shot of the same hapa chini.

haikuwa na users manual?

Hiakua nayo, Ni ya Kuferry Kutoka majuu.

https://www.youtube.com/watch?v=SKy1ZyXAb5c