plain language please

I've plunged into an assortment of goodies lately: ambient intelligence, usability testing and interactive digital tv. I'm lying in our raspberry red couch in the lab, reading articles and papers, and thinking that ICQ inc could use a copy of the ten rules for user interface design by the web page usability guru Jakob Nielsen. In particular, I'm thinking of number 9:

"Help users recognize, diagnose and recover from errors: Error messages should be expressed in plain language (no codes)".

I'm using icq v 4.1 and increasingly more often while instant messaging; I'm suddenly unable to send off messages. The error message that appears explains the problem only by a code. That’s not what I want, I want a brief, easy to understand message that explains what happened. Therefore, the word on my mind right now is heuristics.

According to Nielsens website, new findings on usability guidelines for websites is to be presented at the Usability 2005 conference, in Stockholm among other places.