I tried running 3 different Mac OSX desktop apps to post outside of MT: Kung-Log, EspressoBlog and NetNewsWire. None of them works. Apparently, the xml-rpc.cgi is misbehaving on my blog: when it tries to retrieve a list of my categories it gives me an error message (XML-RPC call failed).
I include here the full Kung-Log error msg:


What could possibly be wrong? All I can think of is that I added a string to change the hieranchy of  my individual archives within folders named after categories (as of the MT manual):

Could this possibly be the reason?
Any help appreciated, I haven't a clue.
Thank you all.

If you're running MT on an IIS server, there's a bug that effects the way the IIS uses SOAP::Lite.

To fix it:

In the MT\ExtLib\XMLRPC\Transport directory, open the HTTP.pm file. Add the following line:

undef $ENV{SERVER_SOFTWARE};

before this line:

@XMLRPC::Transport::HTTP::CGI::ISA = qw(SOAP::Transport::HTTP::CGI);

There's a more detailed explination at RandyRants.com.

HTH!

If you see "Encountered string encoding error", it is most likely your blog name and/or your category names have accented characters like é and such. Those will break the parser in Apple's WebServicesCore and as such Kung-Log. To fix it, convert the accented characters in your name with proper HTML entities (for a list see: http://www.evolt.org/article/comment/17/21234/). Make sure to use numeric HTML entities, btw, for compatibility with Kung-Log.