java.security.Invalidkeyexception: supplied key (null) is not a RSAPrivateKey instace

Hello, I have been struggling for weeks now to setup openfire server to my enterprise for secure chat. I want to provide SSL connection. I follow the steps in “SSL guide” documentation, using keytool. I export my cert request and send it to CA in CSR format. When I get my cert I first import root cert, then intermediate and server cert as last. but when I restart openfire I get the error: java.security.Invalidkeyexception: supplied key (null) is not a RSAPrivateKey instace. To test, I restarted openfire after each step. I noticed that this error comes rigt after I add my root cert to keystore. please help me to find a way to add my cert files to openfire and make ssl work. I have been spending a lot of time but google searchs did not help me to find the correct answer. thanks in advance…

I tried with both Openfire 3.6.4 and 3.7.0b. I use jdk 6.0 (if matters). Any clues?