Plugins quit working

okay we are running WP version 2.0.1 and everytime we instal plug ins. They work for like a hour, then we come back a few ours later and its as if we never installed them. However when you go to the plugins section of the dashboard it shows the plug ins are installed and activated.

We are running the following plug ins:

EditorMonkey

Hello Dolly (this one is deactivated)

Usayd’s Islamic Praise

WP-PostViews

WP-Polls

WP-PostRatings

Spelling Checker

Text Control

WordPress Database Backup

One exception this has happened twice however both times the poll plugin continues to work.