Configuration Error

i just unlocked my c510 using aerix and it was working fine for about 20 minutes then i copied my contacts from my old phone onto the sim and then put the sim in my c510 and i got this error message

"Configuration error. Please contact your network provider or service centre"

does anyone know how i can rectify this?

thanks

Read here : CONFIGURATION ERROR - Answer is here - Top Sony Forums
if you are confused which file to use, just post log from A2 uploader

you simply need to add custpack..