Doing some basic research online, I found one instance where a WordPress user received a "Requested Range Not Satisfiable" message because they were using a caching service called Varnish. Sometimes, web hosting companies use caching services like this at the server level. So, it's not something you'd have access to from within your WordPress dashboard.
In another instance, a user was using a second podcasting plugin on their site. If you've got any other podcasting plugins active, deactivate and delete them.
Also, I've asked Blubrry's lead developer to look at your question. Either he will reply here directly or I will reply for him once he's had a chance to look at your situation.