It sounds to me like Sigma is the problem, if DSB have an ounce of credibility they'll be investigating this and IF it is a case of piracy of Robs work they'll take it off their books and take some kind of action against Sigma.
All we can really do is watch what happens, slinging rocks at one another and screaming isn't going to help.
I just hope Rob gets this sorted, as he has made great contributions to this hobby and I'd hate to see him quit.
Ozzy
From reading parts of the (exceedingly huge) thread of Avsim it appears that DSB and Sigma are both DBs companies - DSB now just being the "distribution" part of DBs company .
However, just because Sigma developed the package in question, it doesn't mean he made all the components of it, and from what I understand it was a sub-developer who provided DSB/Sigma with the XML file in question, which appears to be a copy of one of Rob's files, so I wouldn't jump to conclusions just yet. I'm sure this has happened before but people have got away with it...