error compiling Open Inventor programs

[Mr D P Williams <esuvs@csv.warwick.ac.uk>]

Hi,
    I have just started experimenting with Open Inventor, and have hit
immidiate problems. My program simply creates a sphere with materials,
but when I try to compile it I get an error like the following:

error in file included from SoSeperator.h:
    class SoError has virtual functions but non-virtual constructor
    class SoDebugError has virtual functions but non-virtual constructor

I installed Open Inventor on RedHat 7.0, and I am using it with qt 2.2.3
and kdevelop, GCC version 2.96. My program does not use the two error
classes mentioned in the message.

Thanks in advance for any help,

    David