Sorry, I don't understand the relevance of the search you cite re NN4., 6., and IE 5. The threads found pertain to PM specific issues.

So, making a suposition (which may not be correct) that you're getting an error or warning from a validator that's addressed to the lang and xml:lang attributes

• Older browsers will sometimes choke (even tho they're supposed to ignore what they don't understand) on features that were developed after they were released
• "http://www.w3.org/1999/xhtml" doesn't ring any bells for me (I checked the page) but I'm not doing/using xml/xhtml so I can't offer any ideas there.
• "This HTML Part is gerated by perl... seems to be a statement that the module(s) you're using is creating that line (if misunderstood, please clarify) in which case, you need to take a look at the instructions you're giving it... and the pod or other documentation to make sure it does what you think it does.

Know this may not be terribly helpful, but I'm lost...
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