It is not possible to just 'upgrade' to Slacko from Lucid. To use Slacko requires a new install or live run from DVD required, see Slacko page.
Slackware is design to use Slackware's repositories rather than Ubuntu's. It has different libraries built in as standard. Also Lucid was made with Woof v1
However, some of the utilities and themes from Lucid are available for Slacko in the LupufySlacko package.