Mounting with cifs in BT5 does not work any longer, however the second method does. Even though the hostname is stored in the hosts file. This was not a problem in BT4 and BT4 rt.

using the hostname to mount results in the error code above.
mount -t cifs //hostname/share -o username=,password= /mnt/share

mounting with the ip address is successful.
mount -t cifs //ipaddress/share -o username=,password= /mnt/share