SIP is not a registered protocol (?)



On my web site (http://users.telenet.be/henk.oegema) I have, on the bottom
of that page, two telephones. If you click on one of them, you can reach
me.
This works fine in windows.
Unfortunately I can't get it working in SuSE10.0.
When I click on it, I get message: sip is not a registered protocol.

Is there anyone who has experience with this ?

Rgds.
Henk

.