I've removed the files and the Arduino-editor still errors.

Would an error like

Error inside Serial.serialEvent()

java.io.IOException: Bad file descriptor in nativeavailable

at gnu.io.RXTXPort.nativeavailable(Native Method)

at gnu.io.RXTXPort$SerialInputStream.available(RXTXPort.java:1532)

at processing.app.Serial.serialEvent(Serial.java:215)

at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)

at gnu.io.RXTXPort.eventLoop(Native Method)

at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)

be familiar to anyone? 

you need to go into the arduino source package and copy that rxtx jar file and the native library for it based on your system platform into the processing built in serial library

I'm on a mac so for me its basically this:

right click show package contents on arduino then Contents > resources > java > rxtxcomm.jar and librxtxSerial.jnilib, copy those files into  Processing > contents > resources > java > modes > java > libraries > serial then paste the rxtxcomm.jar in to that folder and then the librxtxSerial.jnilib into the macosx folder. 

I recommend moving the files in there to other directories on your computer first and once you drop them in the Processing serial library, quit and restart to test it.

These file paths will be different if you are not on a mac but basically you need to replace the rxtxcomm.jar in processing and its native interface with the ones in arduino and you will be set regardless of your platform

That sounds really reasonable and straightforward.

The Arduino rxtx-error in my previous post was generated by an erroneous wiring, so my inner chaos has eased out. 

I'll get to it, Thanks.