DBI, Dynaloader, mod_perl, and Undefined symbol "PL_dowarn"

[Jonathan Hilgeman <JH...@ecx.com>]

I just experienced an issue where I upgraded MySQL, and had to reinstall the
DBD::Mysql module to match the new client libraries (libmysqlclient.so.10 -
I was getting messages about an ISA directive not found). After reinstalling
the MySQL module, DBI began to spew errors at me when I tried to restart
Apache. I was running mod_perl 1.24, and after reinstalling DBI, I finally
figured out that I needed to upgrade mod_perl (I went to mod_perl 1.26) and
this fixed the problem. 

This is pretty much just a helping piece for anyone searching for this
error.

- Jonathan