I am not familiar with Jelm but it looks like an error with the JCA (Java Communications API). My guess is that JELM needs the JCA installed. it can be found:
http://java.sun.com/products/javacom...ads/index.html
The documentation on how to install it is a bit sketchy so let my know if you have any probs.
Wait... upon reading your last post it seems you have already figured this out.
The file javax.comm.properties is part of the JCA. It basically tells java that the JCA is installed and how to use it. The JCA is a library for communication through things like serial usb and parallel ports.