need help for ios5 on iphone 3gs

[jess1001]

I've installed ios5 on my iphone 3gs.
the previous software was 3.1.3
but after ive installed ios5 & restarted my phont in order to activate it, the message appeared as below:

The SIM Card Inserted does not appear to be supported.

What should i do?

 

[FreakinEurekan]

Was the phone jailbroken under 3.1.3?

Who is your carrier?