[tlug] Thunderbird RSS different from FireFox?

[Dave M G <dave@example.com>]

TLUG,

This is one of those situations where I'm so removed from any 
understanding of the problem that I'm not sure what questions to ask.

I've created a simple XML file to support an RSS feed for some web page 
content. Works like a charm if I open the XML in FireFox. It reads it as 
an RSS feed and comes up with the usual interface asking if you want to 
subscribe to the RSS feed.

In Thunderbird, it's a different story. When I add the URL to the XML 
file in Thunderbird's RSS interface, it validates as a legitimate RSS 
feed. But when I go to the RSS folder to actually look at the web page, 
I get an PHP generated error saying there is an invalid class name.

The PHP is part of a huge CMS, so I don't want to get bogged down in the 
PHP code, at least not at first. That said, I've seen this error before 
and it usually means that the session has bad cookie data in it that is 
confusing the names of stored variables.

The bottom line is, though, why would I get different results in FireFox 
and Thunderbird? Not only would I have thought RSS was a pretty simple 
thing that would be hard to get wrong, I also assumed Thunderbird and 
FireFox would be largely based on the same code.

What would be some possible avenues to explore to discover why it works 
in one and not the other?

Any advice much appreciated.

--
Dave M G
http://www.tlug.jp/wiki/User:Dave_M_G