hi i have looked at other threads of usb problems i cant seem to find one that matches my error msg

any ideas my usb keybaord & mouse is working btw but my Western Digital Ext HDD 250gb (mybook) isnt also i am wanting to plug my ipod in for syncing with itunes later.

Could not load the Host USB Proxy Service (VERR_FILE_NOT_FOUND). The service might be not installed on the host computer.


Result Code:
0x00004005
Component:
Host
Interface:
IHost {81729c26-1aec-46f5-b7c0-cc7364738fdb}
Callee:
IMachine {f95c0793-7737-49a1-85d9-6da81097173b}