You probably don't have the DNS server set up to map blackbox to whatever blackbox's IP address is. If you don't know what blackbox's IP address is, on blackbox run ifconfig.
eth0 Link encap:Ethernet HWaddr 00:11:43:2F:5B:B5
inet addr:192.168.2.16 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:80028674 errors:0 dropped:0 overruns:0 frame:0
TX packets:224359523 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:38041123059 (35.4 GiB) TX bytes:197635233761 (184.0 GiB)
Base address:0xccc0 Memory:ddfe0000-de000000
This is the output of ifconfig on one of my computers. In this case, the IP address is 192.168.2.16. So, first, just find the part where it says eth0 in the output from ifconfig. THen just look a line below that and see what it says for inet addr.
You can either mount the share on silverbox via this IP address that you just learned. Or, you can put that IP address in the /etc/hosts file and map it to a hostname. In /etc/hosts on silverbox, add a line that say
<IP Address of blackbox> blackbox
Then you should be able to access the share on blackbox by just using the name blackbox, not its IP address.