How to disable Gallery2 Guest User Password

Hi,

I installed PostNuke .764 and embedded Gallery2 using the mGallery module. I also synchronised the PostNuke users with Gallery2. Everything works fine when I log in as a member to PostNuke and then access Gallery2 - GREAT!!! However, when I do not log in as a registered PostNuke user and access Gallery2 I am asked for the Guest user password and cannot progress further!!! Is there a way to remove the guest user password login so that unregistered users can visit Gallery2? I tried deleting the Guest user, but doesn't seem possible. I tried removing the guest user password, but I can't seem to find where I can do this. I know the guest user password as I configured it during the installation, but now I can't seem to remove it????
Alternatively, I can specify the guest user password for unregistered users to use, below the Gallery2 plugin, but I'm not sure which file to place the text in.

Any assistance would be greatly appreciated.

Regards,
Kevin.