Same problem here: wordpress 3.0.4 with php and mySql both current versions.
1- installed using auto-install from plugins admin, Add New.
2- installation reported "extra characters...header" etc about 116 chrs (sorry did not capture that, then).
tried to load 'settings' page from plugin admin - never loaded.
3- Deactivated plugin, waited ~ 10 mins.
Reactivated plugin and NO ERROR Messages during Activation.
tried to load 'settings' page...never loaded (browser Mozilla page loading icon just spinning - no timeout message after 4 minutes). Trying Delete Plugin then reinstall next
4- Deleted plugin, (removed all files. yes all were in the plugin's folders).
5- tried automatic install again - via Add New.
Successfully installed the plugin Yet Another Related Posts Plugin 3.1.9.
clicked "Activate Plugin" No Errors - Yea!
from Plugins Page, clicked 'Settings"
Oops! well it started to load up; showing spinners in the categories list and tags list areas, etc. Then the page goes blank. Pressing the Back-arrow on the browser begins to draw the 'settings' page but the areas with variables (categories list tags list etc) showing only spinners and after a few seconds the page goes blank - yikes!
6- trying in Chrome browser instead of Mozilla 3.x
navigated directly to the Plugins page. Clicked 'Settings' pages begins to appear (again, with spinners in the area of the page titled, "The Pool"
After a few seconds the settings page goes blank
7- ... Hope to see some suggestions about this in the future here on this forum.
This plugin works well and without any problems whatsoever on other blogs i manage,l but not this blog... sorry, don't have the time to deactivate every plugin and see if one is conflicting (a likely cause me thinks)... I'll check back soon ;-)