Con Xmarks into XP the Favorites Folder is a "Virtual Folder"

I work with 2 PC, a Linux Ubuntu 9.04 and a PC with XP.
With either PC I use Firefox 3.5.02.
All O.S and programs are in Italian.

On the PC XP I have over 2.500 favorites managed in more trees with many folders.
Also, I've in the "Favorites/Links" folder more shortcuts to the docs and the programs into PC or to some network references.

Last week I've downloaded and installed Xmarks for IE and for FF and I've started the Sync.

Now I've into Bookmark of FF, into Favorites of XP and into MyXmarks Server 3 Favorites folders and 2 trees di URL.

Furthermore, in some folder all the shortcuts to files or the folder personalizations (like new icons) are lost.

But the great problem is that into XP the Favorites folder and its subfolder are "virtual" folders.

At example, if I copy (copy, not move) the Favorites folder from disk C: into disk D:, when I open D:\Favorites the address bar in Explorer reports the path into disk C:.

More, if I rename the d:\Favorites in d:\Favorites2, also the original Favorites folder into disk C: change the name!

I've unistalled Xmarks for IE and I've disactivated Xmarks for FF, but the problem remains.

Help me!
I've to reinstall XP?