Guys I've discussed this issue with the MediaMonkey support team and they've come up with a solution!

First this is the solution: http://www.mediamonkey.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=16

You have to add:

[WMDM]
COMApartmentThreading=1

to MediaMonkey.ini. After you've done that MediaMonkey will sync correctly to 3rd Generation Sony Walkmans such as the NWZ-A72x and NWZ-A82x series!

Here's info how to locate and edit the MediamMonkey.ini file:
http://www.mediamonkey.com/support/index.php?loginresult=1&group=default&_m=knowledgebase&_a=viewarticle&kbarticleid=17

The Support team said that this fix will be included in the future in the MediaMonkey 3.1 release which is currently in beta testing.
I want to thank the Support team once again for their quick and helpful reply to finally solve this problem.
MediaMonkey ftw! :D

Yeahh, the same with my new A828 :(

Any news to slve this problem?

Tks

Hi,
I have the same problem with my Sony A818 and I tried like you everything but nothing work.
If someone can helps us that would be nice.

Hi,

I just got my Sony Walkman NWZ-A729 (nice sound), upgraded MM to Gold en was ready to sync....

However..

It copies al my MP3-s to the root directory.

How can I fix this? I have changed every path possible in de device options (\musis\<album> or \Walkman\Storage Media\MUSIC\.... or Computer\Walkman\Storage Media\MUSIC). Even leaving out a directory doesn't prompt MM to make one.
Syncing with windows media player does work (without special setup), but I did not buy MM for that.
I can manually copy albums using Windows Explorer.

I hope anybody has a solution???