my psp problem

currently my psp 2000 was in 5.00m33-6 but it cant to play lan game..i dont know why,any solution plz?when i press multiplayer game option it will hang and then shut off my psp or i search my brother's psp game but i cant join it...but i has tried my psp to use wifi on9..its working fine..i can go all the web page..please help..and i wan to ask the best price for psp go