Hmm… I don’t get that “+PACSP: 1” line, when I power on my GPRS shield.
“PACSP” is “Network Selection Menu Availability”.
Do any other commands work? “AT”? “AT+CREG?”?
Is your SIM card active? Have you tried it in a phone?
But first – have you set line ending symbol as “carriage return” in your terminal program?