After installation, no access to user and plugin control

Hallo
i tried twice to install the plugin, it works great, but after installing i had no access to control user settings and even no control to plugin settings and even site editing was disabled.
This is not practical for me, is there an work around so i have full control of the WP site when the plugin is installed. Normal disabling of the plugin was not possible also. I had to rename the plugin manually with the FTP, of course all operations were made with an admin account.
Thx Uli