Fatal Error after plugin installation?

Hi, I’ve installed the latest version of the plugin and duplicated some new drafts in my pages section. Then I’ve put these new pages into a new custom menu and saved it. After that (and I’ve changed nothing else) I receive this error message in my frontend when I call a page with the menu with the duplicated posts:

Fatal error: Out of memory (allocated 63963136) (tried to allocate 32 bytes) in /homepages/33/d459824627/htdocs/augustinianum_2013/wp-includes/wp-db.php on line 1551

Furthermore, I cannot access the View all section in my pages backend and I get the same error message when I want to access Appearence –> Menu section in my backend.

Can there be a problem with the plugin?
Best regards, Andreas

http://ww.wp.xz.cn/plugins/duplicate-post/