I think I solved the problem now. I also placed a question on ubuntuforums.org, and I got a tip here. What I did was replace the lines
Listen localhost:631 Listen 10.0.0.145:631
with the line
Listen 0.0.0.0:631
in the cupsd.conf file.
Now I can access the CUPS web interface on my server from a client machine in the network.
I think I solved the problem now. I also placed a question on ubuntuforums.org, and I got a tip here. What I did was replace the lines
Listen localhost:631
Listen 10.0.0.145:631
with the line
Listen 0.0.0.0:631
in the cupsd.conf file.
Now I can access the CUPS web interface on my server from a client machine in the network.