ifenslave error in Channel Bonding

[Hao He]

Hi, all.

I am trying to bond our cluster with 3C905 cards.
Since my Linux distribution is SuSE 6.1 (2.2.5 kernel upgraded to 2.4.4), I have to run ifconfig and ifenslave at command line.
Finally I got success in one try, I think, but failed in all others. I am confused. 
Here are the details. When I ran 
        ifconfig bond0 192.168.1.1 up
No error prompted. When I check ifconfig, I find that bond0 got IP 192.168.1.1 and 
HWADDR is 00:00:00:00:00:00. Seems it is OK. Then I ran
        ifenslave bond0 eth0
I got following error message:
        SIOCSIFHWADDR on bond0 failed: Device or resource busy.
        The master device bond0 is busy: it must be idle before running this command.
What's wrong?

Could you tell me how to correct this problem?
Your advice will be highly appreciated. Thanks a lot! 8-)

Best regards,
Hao He