It's more helpful to give an idea of what kind of system you're talking about.
Just for grins, I'm going to guess Ubuntu Linux.
You could do exactly what it says: read the manpage for ln(1) for more details on symlinks, but:
ln -s /usr/lib/libgdbm.so.2.0.0 /usr/lib/lbgdbm.so
might just fix your problem.
It might not, because there are so many other things that could affect this and you have not narrowed down the field much for us.
I would suspect that a better approach would be to use your system's native package manager, if my guess at ubuntu is correct, I think you want:
apt-get install libapache2-mod-perl2
If the native package manager approach won't work for you, even more reason why you need to give more information and write a better question.