[Plugin: SitePush] login problems, mixed

Have you explicitly defined the site url in your dev wp-config.php file? If not, that should do the trick. In your wp-config.php file for the dev site add something along the following lines:-

define('WP_SITEURL',"http://dev.example.com/wp" );
define('WP_HOME',"http://dev.example.com");

or whatever is appropriate in your install. I would also put the equivalent lines in wp-config.php for your live and other sites too, so that wherever you are pushing from/to, WordPress always knows what the correct URL is for any given site.