PAMGuard is failing to read configuration data from National Instruments in 64 bit versions of PAMGuard. This only applies ot the first card in the list within the NI_MAX configuration software. There is no short term fix. The work around is to add a simulated device to the top of the device list in Ni-MAX and have the card or cards you want to use listed after the simulated one. Clearly if you want to test with a simulated device, you'll need to add two simulated devices and use the second one.