[Plugin: Mobile Smart] Cookie not set?

I have some problem with the current release of the Plugin (V1.2): The Mobile/Desktop state is not stored. Cookie ist not written – neither in the mobile theme nor in the desktop theme.

http://tuxerhof.at/?mobile_switch=mobile -> the mobile theme is used
http://tuxerhof.at/?mobile_switch=desktop -> the desktop theme is used

I tried to deactivate all plugins except of the mobile-smart plugin – but this had no affect. Has anyone an idea?

http://ww.wp.xz.cn/extend/plugins/mobile-smart/