Program verificaion failure

I am trying to program an EP3SE50F484C2 in FAST ACTIVE SERIAL mode using an EPCS16 configuration device. I have compression turned on. It worked the first time with a passing verification. The second and all subsequent time verification fails. I have replaced the EPCS16 twice with no success. When run examine I get a different check sum each time, as if it were reading garbage. I have programed the gate array using the JTAG port successfully and the programed EP3SE50F484C2 operates properly. What can I do short of replacing the gate array.

Thanks for your assistance