Have you tried 'mapping' from the command line?? That may (or may not) give you a more informative error message. Try the following commands from a command prompt:
net view \\dns323_ip_address
net use n: \\dns323_ip_address\Volume_1
Obviously you'll need to replace dns323_ip_address with the IP address or name of your NAS and may also need to change the Volume_1 at the end of the second command if you don't see that name in the list returned by the net view. If the first command gives an error then the second almost certainly isn't going to work either. Cut and paste the contents of the command prompt window into a post here if you can't make head nor tail of the responses and we'll see if we can help further.
Here are the results, I had done this before with the same results as before...
C:\Users\stratplayer>ping 192.168.0.97
Pinging 192.168.0.97 with 32 bytes of data:
Reply from 192.168.0.97: bytes=32 time<1ms TTL=64
Reply from 192.168.0.97: bytes=32 time<1ms TTL=64
Reply from 192.168.0.97: bytes=32 time<1ms TTL=64
Reply from 192.168.0.97: bytes=32 time<1ms TTL=64
Ping statistics for 192.168.0.97:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
C:\Users\stratplayer>^V
C:\Users\stratplayer>net use * \\192.168.0.97\Volume_1
System error 67 has occurred.
The network name cannot be found.
C:\Users\stratplayer>net view \\192.168.0.97
System error 1707 has occurred.
The network address is invalid.
C:\Users\stratplayer>