hi ckett, have you tried setting the buffer higher (e.g 256 or 512)? Try it and see if the click goes away. If it does, then that's you're problem - although the RME device will run at extremely small buffer sizes (i.e. low latency), it depends how well your system is optimised.
You should be able to run at 512 buffer size without noticing much latency in operation (it's 12 ms I believe), unless you're monitoring through the DAW itself - if you use the RME mixer for monitoring you can have the buffer size as high as you like, still with near zero latency for monitoring.