Plugin parameters not working

I’ve been uploading some new plugins for my newest website which is a review site. Some of those plugins include Xavin’s Review Ratings as well as Simple Tags. Anytime I try to post the parameters to make the plugin show up in a page, sidebar or post (example: [xrr rating=4/5] or [st-tag-cloud]) they do not show up. What am I doing wrong? Most of these plugins say to simply put the parameter where you want the text or plugin to show up but i haven’t been able to get them to work…