The NNTP library doesn't belong to tiki but it is a PEAR library.
To fix that we have to ask for an update/fix to the PEAR guys - or we have to rewrite the library.....
The point I know is that it is working for news.php.net
I suppose that microsoft is still outside the standard
Can you do a bug report on Sourceforge not to forget the point
Ps: you can also avoid the notice message to appear by configuring the php error report in admin / general