wefreema

Apart from security concerns, if all users have admin access to your demo, some clever jerk will probably ruin the demo by changing some settings unless you really secure your installation. At best, they’ll change your theme/settings or upload images. At worst, they’ll hack your server or database. I would recommend screenshots as a better option.

If you do insist on doing this, be sure you set your files to at least 644 and your folders to at least 755 on your host. Don’t allow write access to anything. I would also disable uploading through php. Also, only allow “select” access to the database. I’ve never tried doing it, but I think after the initial configuration, it should work–as long as you don’t ever need to post or change anything.

That nologin plugin will probably work–it’s only 6 lines of code. Basically, it overwrites the wp_validate_auth_cookie() function, always returning true. You’ll note it says “only for local installations”, citing security concerns.

Are you guys still stuck on this?

add_query_var is located in wp-includes/class-wp.php

Does that file exist? Does the function exist? (should be line 93)

Wes