Why my windows xp guest abnormal exits

[shimanshe]

Host:ubuntu 8.04
Guest:windows xp
I have another windows xp on my disk,
So I access the file on the windows xp disk in ubuntu through /media/disk_vol*
Now I allocate the directory "/media/disk_vol*" to my virtualBox guest
use the command : net use x: \\vboxsvr\sharename
That works success.
But when I browse files on my virtualBox guest windows xp,
if I go into directory a little deep , my guest windows xp exits abnormal
No other Information,the guest window just disappears?

[shimanshe]

Very strange:
Only when I access disk D can cause the problem,
disk E,F,..is Ok
the ubuntu is between my windows disk D and E
do this matter?