in reply to howto uninstall a package/module
I solved it all by uninstalling DBI and cpan install Bundle::DBI. Whew.
How did I uninstall? Followed the instructions google gave me.. namely search and destroy. In my paranoia I don't destroy and will never know where things should go back if everything breaks, so..
I ran locate DBI.pm to find the various places it hides in the perl tree. At one point I think/hope I did a find . |grep DBI.pm since locate was not up to date but.. okay so I found a bunch of paths ending in DBI.pm.
Basically I renamed all folders called DBI to DBI_old and all DBI.pm files renamed to DBI_old.pm without moving them anywhere. This salved my paranoia (I could grep for DBI_old later on) and my machine is happy. I am wanting to upgrade my perl though.. my other machine is a 5.8.8. (on which various modules like SQL::Statement discover make tests need patching).
Hope this helps. I just pondered the potential merits of saving records of installation sessions on a per-session basis for roll-back but my mind almost melted down. Have a nice day!