Can anyone solve the following problem for me please?

I happened to see an article talking about Building a Skype Server for Your Home Phone System in Ithe ssue 141 of the Linux Journal. I have followed all the steps mentioned in the article to set up a Skype Server by using Fedora Core 3. Everything was fine, but there was only one problem that i encountered, that is, while i picked up the landline phone and dial the numbers, it cannot make phone calls. I have tried several other regular phones. But they did not work as well. However, there was ringing sound when someone called me, and i was able to answer the phone call.

As I could not find any solution for this problem, thus, it will be highly appreciated if anyone could give advice for me.

Thanks!!