and when i uploaded the slave.pde with the shield.. I got the error: avrdude: stk500_getsync(): not in sync: resp=0x49
what should I do?
this is expected and normal. Your shield when connected uses the RX & TX pins your Arduino needs for programming over USB. To program, leave the shield off, then when the shield is on all serial traffic is via that, not the USB cable.
There is a link on that user manual to e-gizmo.com for instructions on how to pair it with your other Bluetooth devices. As a slave the other device will need to initiate the connection.