Gamerz - I think there may be a bug with the latest release of WP-PostRatings. I updated it automatically through the plugins section of WP 2.6 to version 1.31.
Here's what happened after the upgrade from 1.30 to 1.31 in WP 2.6. When checking out my homepage, I noticed an entire widget section was blank where the 'Most Rated' PostRatings would be. I went to the widget section and noticed that a non-functional 'Most Rated' widget was more or less 'frozen' in the 'drag and drop' area with no way to remove or replace it. Unable to really do anything, I disabled the PostRatings Widget plugin. My theme's default widgets showed up. Good so far.
I re-enabled the widget plugin and the same symptoms were back. Essentially, you're unable to select either the 'Most Rated' or 'Top Rated' widgets *OR* modify/remove/relocate any existing PostRatings widgets that were in place prior to the upgrade.
Here's a screenshot:
Upon trying to add another widget (say a text widget), the PostRatings widget axes anything you try to add and save - only showing the screwy, non-functional widget. Notice in the screenshot that it says I'm running 3 widgets in that sidebar, but the only one visible after the upgrade is the non-functional PostRatings one.
I don't know if it's 'critical' per se, but it does severely wreck the widget side of the plugin. For now, I'm going to find a backup and roll back to 1.30 until you can take a look at this.