"The server may not exist or it is unavailable at this time. Check the server name or IP address, check your network connection, and then try again."
It's pretty annoying. I was in the process of a back up through time machine when I noticed that it wouldn't connect. I hope there is an easy fix. I know it had issues prior to the DSM 3.2, but thought that was fixed. And since I don't see anyone else complaining about the 4.0 upgrade, I'm sort of confused about this.
I tried it with my desktop (10.6.6) directly connected as well, and the finder is unable to connect. It seems like the only way I can connect to my NAS now is through the web viewer.
The only thing that I set up since the DSM update was setting up an DDNS for remote access as well. I disabled it, and attempted everything again, but with no luck.
I have restarted everything about 5 times. Computer, NAS, router, modem have all be restarted. This is extremely frustrating.
UPDATE: I also tried connecting via LAN with my Windows 7 partition on my desktop and it will not connect. All three setups cannot connect through the network, only through the web portal.
Wow... I completely forgot that I posted this awhile ago and left every one hanging after I figured it out. Well I didn't technically figure it out. I contacted the support team (which have been very helpful) and they gave me instructions that fixed the problem. I apologize this is so late, but hopefully it helps some people in dispair.
1) Go to Control Panel -> Win/Mac/NFS
2) Disable Windows File Service, Mac File Service in those two tabs.
3) Reboot the DiskStation
4) When its back up re-enable Windows File Service and Mac File Service.
5) Reboot your computers that are on the network
6) Then try to mount/map shares and browse the network for it.
I feel like a jerk for not posting this a few months ago after coming back here and finding out that so many people had the same issue. I hope this makes up for it!