Last update: February 28, 2013

If you have upgraded to Debian 6 (Squeeze), you might see this message while running an application (such as Lotus Domino® 7, for example):

error while loading shared libraries: libstdc++.so.5: cannot open shared object file: No such file or directory

And, like me, you might assume that doing this might solve it:

aptitude install libstdc++5
OR
apt-get install libstdc++5

WRONG!

For me, attempting to perform the install in this way lead to segmentation fault for any commands typed after the install -- effectively making the OS unusable!

Here's how to install libstdc++5 on Debian Squeeze:

("$" = shell prompt)
$cd /tmp
Get the libstdc++5 package:
$wget http://http.us.debian.org/debian/pool/main/g/gcc-3.3/libstdc++5_3.3.6-20_i386.deb
this is only one Debian mirror, you can find one closest to you here.

Extract the desired libraries and copy them to the right location
$sudo dpkg-deb -x libstdc++5_3.3.6-20_i386.deb libstdc5
$cd libstdc5/usr/lib
$sudo cp libstdc++.so.5.0.7 /usr/lib/
Note that this differs from Ubuntu which would require copying to /usr/lib32/

$cd /usr/lib
Create symbolic link
$sudo ln -s libstdc++.so.5.0.7 libstdc++.so.5

That's it. Hope this helps you!

Updates:
February 28, 2013: Fixed minor grammar error
May 12, 2012: Added tweaks and clarifications.