Membership plugin and query posts content not showing

Hi there - I love the Membership plugin but am having a problem that, try as I may, I can't solve.

I have set up two levels, one for strangers and one for members. The only difference between permissions is that strangers can't access a Gravity Post form. That is all working as it should.

However, I have a CMS type home page which I'm trying to pull recent post titles into registering another sidebar in the functions.php file and then using either a shortcode insert widget plugin or an execute PHP plugin to call the widget content in the defined area on the home page. Most widgets work in this area, so I think I'm doing things correctly. However, neither the recent posts widget nor Justin Tadlock's Query Posts plugin/widget will work in this area. It's as if the Membership plugin is preventing a query being run in this way. And I say that because, when I'm logged in as admin, both the recent comments widget and Justin's widget work as expected. There's no shortcode option that I'm not ticking for viewable content and I have selected the relevant blog categories as being visible, which leaves me at an utter loss.

Can someone please help?

Many thanks.
Richard