pin location AB15 (pad_214) is too close to VREF

Hi all

I meet one error when run Quartus10.1 to implement cyclone4-115-f780 (EP4CE115)

Error: Output or bidirectional pin COMMON_I[8] in pin location AB15 (pad_214) is too close to VREF pin in pin location AA15 (pad_213)

Error: Output or bidirectional pin COMMON_I[8] in pin location AB15 (pad_214) is too close to VREF pin in pin location AA15 (pad_213)

Error: Output or bidirectional pin COMMON_I[14] in pin location AF21 (pad_239) is too close to VREF pin in pin location AC18 (pad_240)

Error: Output or bidirectional pin COMMON_I[0] in pin location AD12 (pad_182) is too close to VREF pin in pin location AB13 (pad_181)

Error: Output or bidirectional pin COMMON_I[0] in pin location AD12 (pad_182) is too close to VREF pin in pin location AB13 (pad_181)

Error: Output or bidirectional pin COMMON_I[0] in pin location AD12 (pad_182) is too close to VREF pin in pin location AB13 (pad_181)

Error: Output or bidirectional pin COMMON_I[8] in pin location AB15 (pad_214) is too close to VREF pin in pin location AA15 (pad_213)

Error: Output or bidirectional pin COMMON_I[8] in pin location AB15 (pad_214) is too close to VREF pin in pin location AA15 (pad_213)

Error: Output or bidirectional pin COMMON_I[8] in pin location AB15 (pad_214) is too close to VREF pin in pin location AA15 (pad_213)

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according to <<EP4CE115 Pin Out.xls>>, PIN_AB15 is next to VREFB4N2(PIN_AA15)

I have ever tried to add constraints:

set_instance_assignment -name IO_MAXIMUM_TOGGLE_RATE "0 MHz" -to COMMON_I[8]

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but this constraints does not work.

so, do you have some suggestion? thanks very much