[Users] "No ploop support" message on Centos 5 with vzctl 4.7

[Aleksandar Ivanisevic]

Hi,

I'm running Centos 5.10 with 2.6.18-371.6.1.el5.028stab112.3 and
recently upgraded to vzctl 4.7

Now every time I start vz or do a vzlist I get a 

No ploop support in the kernel, or kernel is way too old.
Make sure you have OpenVZ kernel 042stab058.7 or later running,
and kernel ploop modules loaded.

Other than that I haven't noticed anything wrong.

What does this message exactly mean? What can I expect to fail? Can the
message be turned off somehow? 

regards,