When activating the plugin on WP2.7, I get the following fatal error:

Warning: include_once(lib/debug.php) [function.include-once]: failed to open stream: No such file or directory in /var/www/home/kodama/design/public_html/wp-content/plugins/role-scoper/role-scoper.php on line 135

Warning: include_once() [function.include]: Failed opening 'lib/debug.php' for inclusion (include_path='.:/php/includes:/usr/share/php') in /var/www/home/kodama/design/public_html/wp-content/plugins/role-scoper/role-scoper.php on line 135

Warning: require_once(lib/agapetry_lib.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/home/kodama/design/public_html/wp-content/plugins/role-scoper/role-scoper.php on line 146

Fatal error: require_once() [function.require]: Failed opening required 'lib/agapetry_lib.php' (include_path='.:/php/includes:/usr/share/php') in /var/www/home/kodama/design/public_html/wp-content/plugins/role-scoper/role-scoper.php on line 146

Of course! I re-uploaded the plugin and now it has activated without issue.

Thanks so much for your reply - I should've figured that one out for myself, but all those bold error messages freaked me out.