I have spent quite some time to get the serial communication between Processing and Arduino working. Unfortunately I haven’t succeeded yet. It’s either some vagabonding libraries or a 64bit incompatibility issue. The only information according this error was in the Processing wiki and in a messageboard thread. They recommend to manually replace some jars and dlls, but their troubleshootings didn’t work yet. I still have to try another specially 64bit compiled version of the RXTX library. I watched thru several serial communication tutorials (1,2,3,4,5), hoping to find some more informations according this error. I also stumbled over the CmdMessenger Library, which sounds like a interessting solution for the serial communication (CmdMessenger on GitHub). I also got the Eclipse plugin for Processing, but the same here. Right now I don’t know, if I should just put a fresh Windows version on my pc or if I should keep on trying to solve that error elsewise! So for the moment, I stepped back to the Arduino Code which already worked but hasn’t had the perfect formatting of the IDs in decimal.