I used installed and activated this plugin and it would not let my site return anything but a white screen. It seems to be a plugin conflict, rather than a conflict with WP core. Are the plugin functions uniquely prefixed?
from: http://codex.wordpress.org/Writing_a_Plugin#Plugin_Development_Suggestions and http://nacin.com/2010/05/11/in-wordpress-prefix-everything/
All the functions in your Plugin need to have unique names that are different from functions in the WordPress core, other Plugins, and themes. For that reason, it is a good idea to use a unique function name prefix on all of your Plugin's functions. A far superior possibility is to define your Plugin functions inside a class (which also needs to have a unique name).
FYI: I am also running: http://wordpress.org/extend/plugins/yet-another-related-posts-plugin/, but I am not sure that this is the conflicting plugin... it would seem that this is a logical place to start asking the question.