certificate/key mismatch

I have been trying to create a self signed certificate for the Apache on the virtual server and import the key and certificate to the BIG-IP. But I keep get "Import Failed: Certificate/Key mismatch" error. Can anyone point out what is wrong in the following steps I followed?

1. Create a private key for Apache using

openssl genrsa -des3 -rand file1:file2:file3:file4:file5 -out server_f5.key 1024

2. Remove the pass-phrase from the key using

openssl rsa -in server.key -out server.pem

3. Generate the CSR using

openssl req -new -key server.key -out server.csr

4. modify the 40_mod_ssl.conf file to include the following configuration (I have also setup three apache virtual server on 10.40.13.1):

  
    LoadModule ssl_module    modules/mod_ssl.so
  
ServerAdmin ylin@doc.state.ne.us
DocumentRoot /var/www/localhost/htdocs
ServerName www.f5test.com
ScriptAlias /cgi-bin/ /usr/local/apache/share/htdocs/cgi-bin/
SSLEngine on
SSLCertificateFile    /root/server_f5.crt
SSLCertificateKeyFile /root/ssl.key/server_f5.pem
SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
CustomLog /usr/local/apache/var/log/ssl_request_log \
        "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
ServerAdmin ylin@doc.state.ne.us
DocumentRoot /var/www/localhost/htdocs
ServerName www.f5test1.com
ScriptAlias /cgi-bin/ /usr/local/apache/share/htdocs/cgi-bin/
SSLEngine on
SSLCertificateFile    /root/server.crt
SSLCertificateKeyFile /root/ssl.key/server.key
SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
CustomLog /usr/local/apache/var/log/ssl_request_log \
        "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
ServerAdmin ylin@doc.state.ne.us
DocumentRoot /var/www/localhost/htdocs
ServerName www.f5test2.com
ScriptAlias /cgi-bin/ /usr/local/apache/share/htdocs/cgi-bin/
SSLEngine on
SSLCertificateFile    /root/server.crt
SSLCertificateKeyFile /root/ssl.key/server.key
SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
CustomLog /usr/local/apache/var/log/ssl_request_log \
        "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
ServerAdmin ylin@doc.state.ne.us
DocumentRoot /var/www/localhost/htdocs
ServerName www.f5test3.com
ScriptAlias /cgi-bin/ /usr/local/apache/share/htdocs/cgi-bin/
SSLEngine on
SSLCertificateFile    /root/server.crt
SSLCertificateKeyFile /root/ssl.key/server.key
SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
CustomLog /usr/local/apache/var/log/ssl_request_log \
        "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"

5. Add Include /etc/apache2/modules.d/40_mod_ssl.conf to httpd.conf on 10.40.13.1

6. restart the Apache on 10.40.13.1

7. On big-ip interface, copy the server.pem file content to the key import page. It worked.

8. On big-ip interface, copy the server.csr file content to the certificate import page, it says "Import Failed: Certificate/Key mismatch" error.

Any clue what I did wrong?