Besides mysql client, server, and DBI, you also need the DBI::Mysql portion to be working right, which is what this error suggests (Note that most packaged mysql client packages do not contain the perl glue code, so the version problem is not a result of the client package). Running debian, I know there's a package called (OOTOMH) 'libmysqlclient10', which I would strongly suspect has linkage to the DBI::Mysql portion, and you might be currently using libmysqlclient9.. the version update was changed within the last 3 months, so this might be something that you missed. I'm not sure what you'd look for for a Redhat system, or if you have a different architecture, but that's a place to start.