This is a bogus error message that can be safely ignored - it's caused by the domain join code ending up in a function which it doesn't need to run anyway during a domain join operation using the GUI.
What's failing is the attempt to change the Primary DNS suffix of the machine after the domain join has succeeded - but the Primary DNS suffix is already correct at that point which is why this can be ignored.
The domain join itself is not affected at all and will have succeeded if you're seeing this specific error message with the empty quotation marks as that code is only run after a successful domain join.
As frustrating as it is, this is unfortunately one of those cosmetic issues which aren't likely to be fixed until the next OS version - primarily because it has zero impact and no effect beyond the ugly error message.
A workaround that removes the error message is to populate the Primary DNS suffix of the machine before attempting the domain join.
Footnote: This doesn't repro on Windows 8 or Windows Server 2012
See http://support.microsoft.com/kb/2018583 for further details.
Thanks, the messages was a bit scary :)
Despite the appearance of the on-screen error described in the symptoms section, the domain join operation completes as evidenced by the status in the NETSETUP.LOG
NetpCompleteOfflineDomainJoin SUCCESS: Requested a reboot :0x0
NetpDoDomainJoin: status: 0x0
To eliminate the error, either:
1.Verify that NetBIOS over TCP/IP is enabled.
a) Click Start , click Run , type ncpa.cpl , and then click OK .
b) In Network Connections , right-click Local Area Connection , and then click Properties .
c) Click Internet Protocol Version 4 (TCP/IPv4), and then click Properties .
d) In the Internet Protocol Version 4 (TCP/IPv4) Properties dialog box, click Advanced .
e) On the WINS tab, verify Enable NetBIOS Over TCP/IP is enabled, and then click OK three times.
2.Verify end-to-end network connectivity over UDP port 137 over the network path connecting the client being and the helper DC serving the join operation.
3.If the error occurred in an IPv6 only environment OR you require a fix to resolve the error, open a support incident with Microsoft Customer Service and Support requesting a post RTM fix for Windows 7 and / or Windows Server 2008 R2.