Your plugin will not activate on a WP instance ver 3.8. I followed all your suggestions for deactivating plugins, trying a new theme (used the basic theme that comes w WP), footer hook, etc. Nothing worked.
I happen to be developing another WP site using the same theme with the same activated plugins but it's using WP 3.7. Your plugin activated with no problem.
I am getting a fatal error. Here is an example (but the actual file changes when I try to activate at different times):
Parse error: syntax error, unexpected 'save_post' (T_STRING) in /home6/ameridu6/public_html/education/wp-content/plugins/lightbox-plus/classes/actions.class.php on line 338