Apache claims "NameVirtualHost A.B.C.D:80 has no VirtualHosts"

[kevork]

Hello,

Plesk 10.0.1, just upgraded, Centos 5.5, dedicated server.

Apache claims "NameVirtualHost A.B.C.D:80 has no VirtualHosts" but VirtualHosts are configured by Plesk.
Some clue perhaps?

Thank you a lot,
Jorge.