Can't launch Seamonkey: libstdc++.so.6: caot open shared object file

Hi all,

16.04 LTS and trying to run Seamonkey 2.40 following the instructions here.

I open a terminal, cd to the correct directory and try to launch Seamonkey as per the info given on that link:

./seamonkey

bucky@Studio:~/Downloads/seamonkey2/seamonkey$ ./seamonkey
./seamonkey: error while loading shared libraries: libstdc++.so.6: caot open shared object file: No such file or directory

PS: I've never used Seamonkey so this wasn't working previously and now isn't. Just downloaded and can't launch.