cmd net use can be easier:
https://technet.microsoft.com/en-us/library/bb490717.aspxexample "net use v: \\192.168.1.2\share"
so the network drive is not allowed read/write privileges, for use in HFS?
Double check security to who has read/write access to the drive
is the network drive shared from a linux and/or windows the share?
I have found, that the everyone user is required for HFS to read/write ( a bit insecure to allow everyone, but with at least a test...
windows, it can be a simple permission change:
http://superuser.com/questions/697352/access-denied-when-writing-files-to-network-driveLinux, you have to fix/edit samba config to allow read/write...
As you have just said a nas, with out any other info on what you are using as a nas, it is hard to help you trouble shoot the device. (usually security setting have to be enabled on a nas via there web browsers, depending on hardware...)