hypervisor problem on centos 5.1 as a host

Hi,
I'm having problems with parallels workstation on Linux. My host OS is CentOS 5.1. I tried to install a windows xp as a guest but got a pop-up window with following error message:
Unable to communicate with hypervisor!
I'm also attaching parts of dmesg for more information regarding this problem.
Does anybody have an idea why this happened?

Thanks,
Habib
dmesg output:
[ 6224] hypAllocateCpuIdt: 16 count failed, mode 1
(/home/integrator/PVS_build/drivers/hypervisor/posidt.c:459)
[ 6224] hypAllocateCpuIdt: failed
(/home/integrator/PVS_build/drivers/hypervisor/posidt.c:491)
[ 6224] vmMainIoctl: Monitor PE module not loaded, but [6224] try to send control request to monitor. (/usr/lib/parallels/drivers/drv_main/ioctls.c:299)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] Can't map page directory pointer table. (/usr/lib/parallels/drivers/hypervisor/pages.c:365)
[ 6312] hypAllocateCpuIdt: 16 count failed, mode 1
(/home/integrator/PVS_build/drivers/hypervisor/posidt.c:459)
[ 6312] hypAllocateCpuIdt: failed
(/home/integrator/PVS_build/drivers/hypervisor/posidt.c:491)
[ 6312] vmMainIoctl: Monitor PE module not loaded, but [6312] try to send control request to monitor. (/usr/lib/parallels/drivers/drv_main/ioctls.c:299)

 

Sorry, forgot to add following information regarding the kernel and system:
[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.18-53.el5xen #1 SMP Mon Nov 12 03:26:12 EST 2007 i686 i686 i386 GNU/Linux