Configuration of Movable Type

Hallo,
I'm using Mozilla 1.4 nightly 20030414 and  want to test out Mozblog 
with my MovableType Powered Blog.
I changed the nsxmlrpc.js file.
Then I made a local directory to store Mozblog-Files,
then I proceded to the Server Settings.
I choosed MT and entered as Serverurl: 
http://domain/cgi-bin/MovableType/mt-xmlrpc.cgi .
I entered Username and Password (these are correct) and clicked OK.

Then the checking settings dialog appeared and Mozblog found the two 
Blogs, which are currently in use at my server.
After this it said "Saving details...", and nothing more happened. OK is 
disabled, only Cancel is clickable. If I click Cancel, I cancel the 
Settings-Dialog and I can start the same from the beginning.

Is there anybody out there having an idea, what's wrong?

Maybe this is related to http://mozdev.org/bugs/show_bug.cgi?id=3610 ( 
Add Server entry error for Moveable Type) ?

If it is related, then please ignore my Post, otherwise I would be very 
happy, if I can get help by anyone of you.

Thanks in Advance

Manuel