C500 Error

[Guest 5oni]

Hi I bought the C500 back in Jan and haven't had much problems with it, till now. Whats happened is that I unlocked the phone so I can use it abroad. It was workin good there as well. Silly me- I left the phone there so my cousin is now using the phone there on his local network in Gujarat-India (I think it may even be orange or oranges other network hutch).

Now he's just texted me to tell me that the phones screen shows a message saying invalid simcard. So he tries another sim and this time it fails and shows an error message '131086'

What does this mean and how can it be dealt with?