Could the "Configuration error. Please contact your network operator or service provider" be that you didnt also add in a Custom pack, I did this with my Sony C902, I flashed my Phone and switched it on, and got the same message, then I remembered I had to also add my Custom Files pack to replace icons and the customize script, then after I added the Custom Pack Files and switched the phone back on, all was well :D

It explains it in the A2Uploader tutorial :
a2uploader flashing