some questions about the ALTGX

my soft's version is quartus10.1,device is arria ii gx .

in my design,my questions are shown as below:

Error: The I/O standard "1.5-V PCML" is not valid for I/O pad "rx_data". Only pins connected to the GXB transceiver blocks can use this I/O standard.

but I do connect the I/O standard pin to the the GXB transceiver blocks .