The libstdc++.so.5/6 is installed on most systems, but not all.
To install a missing libstdc++ library, visit http://rpm.pbone.net/ and search for libstdc++ for your relevant distribution. Download and rpm --install it (as root).
Link the installed library from the VNL lib directory, like so:
ln -s /usr/lib/libstdc++.so.6 libstdc++.so.6
Modify as needed for the location of the installed library, as found by (as root, in /)