Cell Phone Help

I dont know if this is the worng section, if so, please close/move the thread. So my cell phone, it can text, call, all that stuff. I am trying to figure out how to picture mail... everytime i click on it it says "you need to register a picutre mail account" then when i click ok, it says error... I can recieve picture mail but i have to go to a url with my computer to actually view the picture. I have a samsung, my service is sprint and its an older model ( ive had it for a while.) i was wondering if anyone could please help.

 

What type of Phone have you got?
And what Phone service provider?

 

ive got a samsung... sprint is my service