Well I can only suggest you to look for the
libstdc++.so.5 library and corresponding packages.
I have never had such error before, and actually that file is in my system:
Code:
~> ls -l /usr/lib/libstdc++.so.5*
lrwxrwxrwx 1 root root 18 2006-03-13 11:41 /usr/lib/libstdc++.so.5 -> libstdc++.so.5.0.7
-rwxr-xr-x 1 root root 732224 2005-07-08 16:54 /usr/lib/libstdc++.so.5.0.7
I can't properly guide you on how to track down a file for Debian packaging