RHEL 5.5 live migration fails in XEN

 I have two XEN hosts, and to migrate a machine has given me an error and has failed to complete the operation.

HOST B  ----->>>>  HOST A

HOST B (RHEL 5.5  2.6.18-194.8.1.el5xen) 64bits and xen-3.0.3-105.el5_5.2:

# cat  /var/log/xen/xend.log.1 | grep -i error

[2012-05-31 07:32:27 xend 5353] INFO (XendCheckpoint:353) ERROR Internal error: domain is dying

[2012-05-31 07:32:27 xend 5353] INFO (XendCheckpoint:353) ERROR Internal error: Domain appears not to have suspended

[2012-05-31 07:32:27 xend 5353] ERROR (XendCheckpoint:133) Save failed on domain www01 (6).

[2012-05-31 07:32:27 xend.XendDomainInfo 5353] ERROR (XendDomainInfo:2259) Exception in evtcnh_reset(6)

[2012-05-31 07:32:27 xend.XendDomainInfo 5353] ERROR (XendDomainInfo:2234) XendDomainInfo.resume: xc.domain_resume failed on domain 6.

[2012-05-31 07:51:52 xend 5353] INFO (XendCheckpoint:353) ERROR Internal error: domain is dying

[2012-05-31 07:51:52 xend 5353] INFO (XendCheckpoint:353) ERROR Internal error: Domain appears not to have suspended

[2012-05-31 07:51:53 xend 5353] ERROR (XendCheckpoint:133) Save failed on domain www01-f5 (7).

[2012-05-31 07:51:53 xend.XendDomainInfo 5353] ERROR (XendDomainInfo:2259) Exception in evtcnh_reset(7)

[2012-05-31 07:51:53 xend.XendDomainInfo 5353] ERROR (XendDomainInfo:2234) XendDomainInfo.resume: xc.domain_resume failed on domain 7.