I've copied the two .dll files okay but with the .jar file there is no folder called 'ext', should I just create a (NEW) 'ext' folder and place in there OR copy it to 'lib' folder that already contains twelve .jar files?
Windows or linux ? What did you follow ? Can you give a link to where that is written ? Which youtube video ?
To install the Arduino IDE correctly on Windows 7 or 10 or linux Ubuntu, remove Java completely. Remove all rxtx java files. They are no longer used by Arduino since years. In linux remove any Arduino from the repositories, and be sure to remove all rxtx java files from the repositories.
Download the newest Arduino IDE 1.8.5 and run that.
This forum is for Arduino. Do you want to use the RXTX libraries for the Glediator software ?
The Arduino IDE 1.8.5 runs without Java installed. When you install Arduino, it also installs drivers for the official Arduino boards, for example for the FTDI chip.
The Glediator software is not Arduino. The Glediator software seems to use Java and the RXTX Java lib. It is not Arduino related. Do they have a forum ?