Vista - cannot access the mapped network drive

I have mapped a network drive successfully with a username and password. I can navigate it in Windows explorer, but when I try to install a software into that drive(when install, there is a panel that I can enter the dest location), it prompts me that the drive is invalid.

Then I click the Brwose button to view the disks, I found it just lists the local disks, the mapped disk is not displaying! It works on XP.

I tried another software, this time I can see the mapped disk from the dialog popup after click "Browse" button, but it displays as disconnected with a red X on it. As I said before, I have connected it successfully, I can create new folder or file on to that drive from Windows explorer...I double clicked the "disconnected" disk from the dialog then it prompts me entering username and password. After I did that, the mapped disk became usable.