page list plus – breaks nav menu theme

one thing i was wanting to do is make the parent pages un linkable – i have found two options which do this
http://bavotasan.com/tutorials/how-to-remove-the-links-to-parent-pages-in-the-wordpress-page-list/
http://wordpress.org/extend/plugins/page-lists-plus/

both work – but once activated – the menu nav theme is taken away

has anybody found a solution to this?