The last version of Slack that I know that WordPerfect for Linux will install and run correctly is Slackware version 7.0. I think I starting having problems with WordPerfect for Linux on Slack version 7.1. I thought it might just an install script issue, so I attempted to install manually with a functioning system as a guide. It still wouldn't operate. Corel had even stopped the support and development before it was sold. There later products for Linux were not really for Linux, but rather ran under wine.
If you would like to read about some of the issues around it, and some of the fixes and work arounds then try this site http://www.linuxmafia.com/wpfaq
They explain fairly well what libraries, X and kernel issues are required. You can then decide if it is worth the effort for you.
I elected to just create a partition on my notebook for Slack 7, configure some simple networking for printer support, and install WordPerfect. But my use is only occasional. With the newer packages that are available, I could not see the effort for my limited use.