The htaccess-Entry works fine for two years (see below). the htaccess-popup only occurs in frontend, when the slideshow plugin is active. therefore i think that the plugin perhaps makes a function call or something from the protected wp-admin-Directory.
some ideas?
<Directory “PATHTO…/wp-admin”>
AuthType Basic
AuthName “Only for Administrator”
AuthUserFile PATHTO…/.htpasswd
Require user USERNAME
</Directory>
