I'm experiencing strange things with my dnn portal but can't figure out what the problem is!

Basically, i've created a portal using dnn. It's quite basic its just using Text/HTML modules etc and the whole site is currently sitting behind a login page.

Here's what happens - When i login as a Host user i experience no problems what so ever, i can browse to any page in my site as you would imagine. But when you login as a standard user (Registered User Role) strange things happen! i'll login and everything will seem fine i.e. i'm redirected to my homepage and can see everything on the page, however when i click to view another page from a link within a content pane (not on the toolbar), the contents of the selected page will load up but the dnn navigation toolbar will dissapear, I'll then click to go to another page and i will be re-directed to the login screen. Its as though it forgets i'm a registered user!

In addition to this, if i login and click on a page listed in the toolbar the toolbar will stay visible even when the new page has loaded, the minute i click a link to a page within a content pane of a page the toolbar will dissappear again!

Some Info that may help

I use <a> tags alot within my site to redirect users to different pages on my portal. As the href for these tags i use the following href="/LinkClick.aspx?Link=347 for a link that will take the user to page 347. Could this be the cause?

I've checked the page permissions on every page and they are either set to be viewable by 'All Users' or 'Registered Users' which is what i am when i experience the problem.

Does anyone know what could be causing this?  Please Help!!