I don't know the kde printer wizard and your printer-model, nor similiar printer-models.
I only setup my parallel-printer with linux so far, and used CUPS to make it available to other hosts, but I guess this is a very different task from setting up a network-printer, with builtin network capabilities.

The printer is using 192.168.0.100 and you use that as gateway-adress too?
This printer isn't an webserver and database-server too.

Port 631 is the internet-printer-protocol port (ipp)
Code:
grep 631 /etc/services
which is used from cups too.

Did you try http://PRINTER_IP:631/?
I guess your Browser will send request on port 80 by default, where normally webservers are listening.