[Libvirt-cim] Problems when using libvirt-cim provider

Hello,everyone: I am trying to use libvirt API and libvirt-cim now. After installed them successfully, I can see the "Virt_*****" providers using "cimprovider -l -s"commond. My cimom is pegasus. Then I used wbemcli as cim client. But when I used "wbemcli ei" to enumerate instances of a specified class,for example,Xen_DiskPool, error code was: wbemcli:Cim(1) CIM_ERR_FAILED: A general error occurred that is not covered by a more specific error code:"For provider Virt_DevicePool the library name was empty. Check provider registered location". Could you please help me to solve this problem? Did it mean that the providers were not registered correctly? But I "make postinstall" the provider and no errors occourred. Thank you! Regards, Chun Shan Disclaimer: The contents of this e-mail, and its attachments, if any, are confidential and may be protected by law against any unauthorized use. If you have received this e-mail by mistake or have reason to believe that you are not the intended recipient, please notify the sender by reply e-mail as soon as possible and delete it from your computer system immediately thereafter. If you are not the intended recipient, you must not copy this e-mail or attachment or disclose the contents to any other person. While we have made every effort to keep our network virus free, we take no responsibility for any computer virus which might be transferred by way of this e-mail.