Hi Buddy
First you can call to your sim operator for getting the internet settings and you can save it on your device..after once check on your device whether the settings saved on your device or not..
For checking it follow the below steps :
Go on Menu -> Settings -> Configuration Settings -> Default Configuration Settings
Here checked it for your access point settings .. it s name displays here..
It is there OK.. then
Second you can set the settings for Video streaming (It is needed for playing the youtube videos )
Go on Menu -> Settings -> Configuration Settings -> Personal Configuration Settings
Here you will get Add New option , there you can select Streaming , after it will shows some settings .........there Use prefer Access point ..select Yes ..
then come back once to Personal configuration settings there now you can able to see My Streaming ..select it and go on options you can click on Activate option ..
Now you Can able to play the Youtube videos.. Enjoy
Note : Still if you are facing any problem Call to Nokia CareLine: 30303838 they will help you