Why can't I get my WordPress plugins to work??

3 of my 7 plugins just won’t work, and I can’t figure out why. they are:
Corrector 0.2
Spolier Tag 0.2
Xhina4WP 1.1

I followed any special directions that were included, and still nothing. They are activated, but…

Does anyone know anything about these plugins, or where I can find suitable replacements?