WP2 – Gallery2 Plugin – saving options gives header error

I’m trying to configure the Gallery2 plugin which I have just activated. It activates OK and I can browse in WP to set the default options but when I click on ‘save options’ I get a header error which points me to admin-header.php. I found a line of empty space, deleted it out and saved the admin header – but when I try to resave the options or browse away from the page, I get thrown out of my domain and cannot get back in (page not found) until I entirely delete out and re-install my wp-admin folder, empty my new database and run the install again – then when I get to the same spot – I get the same error and the same thing happens again (even if I fix the admin-header.php before I run the install). Any one have any idea what’s going on?