This plugin needs a RDBMS supported by DBI with a single table
cf_wrapper_sets. If you use MySQL, you can create the table with the
supplied script create_cf_wrapper_sets.mysql. If you use some other
RDBMS, you may need to adapt it. Note that theoretically, email
addresses may be up to 320 characters long (64 characters localpart + @
+ 255 characters domain name), so if your RDBMS supports varchar fields
of 320 characters or more, you may want to change varchar(255) to
varchar(320) to be on the safe side.