What is the exact message (a screenshot of it would be ideal if possible) and when does it appear?
I'm pretty sure that 48 don't support this OMA Client Provisioning and your SIM PIN is not going to work there.
If you want to configure your internet settings then you follow the instructions here:
I don't know if there's any way to prevent this OMA Client Provisioning message/notification from constantly popping up if it's causing problems/annoyance.
You may need to ask the handset supplier/manufacturer for advice on that front.
Hope this helps.