[libvirt] listDomains() not working on Xen

Hey all, I've been trying to make listDomains() work on Xen but it simply returns an array of null values. Also, while displaying the length of the array returned by listDomains(). Upon using the same function in KVM, I'm able to retrieve the complete array of active machines. I'm positive that active Xen machines are running(cross checked it with xm list). I've been posting this for quite sometime now but haven't received any reply which could debug my code. I'd really appreciate it if someone could help me. Thanks, P Ramesh