1. Are any shares visible on the secondary server using the Secondary Server's channel address in Explorer? Is it possible to map a drive across the channel manually without Heartbeat? e.g. c:\Net use g: \\X.X.X.X\c$ where X.X.X.X should be the IP Address of your Secondary server Heartbeat channel.
If it's possible to map a drive then Heartbeat should also be able to map a drive as the same method is automatically used. Attempt backup again via the installation wizard.
2. Disable and Enable the Heartbeat Channel NIC's.
3. Attempt to ping from both servers to either channel IP Address.
Heartbeat only requires a TCP/IP connection between the servers. This is provided by the Heartbeat Channel. DNS or WINS resolution is not required.
4. Disable any firewalls that are active on the server or server NIC's. This may include Anti Virus software if a firewall is built in. If you are unsure whether your Anti Virus contains a firewall it should be disabled for the duration of the troubleshooting.
5. Is netbios enabled on the channel nics? If not enable on Primary side. If this does not work enable on both sides for troubleshooting purposes. Once the backup has been completed disable netbios once more on all NIC's configured as the Heartbeat Channel.
6. Try both the local or Domain Administrator credentials. The Administrator password should not be blank.
7. Check that the Server service is running, via Service Control Manager on the Secondary server.
8. If after trying the above the servers still cannot establish a connection. Reboot the servers and try the steps again. If you are still experiencing a problem please call Neverfail Support for further assistance.
KB 239 gives details of how to start the backup phase of installation again if required.