Menue crashed when avtivating plugin

Hi,

first of all: i love your plugin, works fine at other sites of mine.
But with one theme i have problems, the submenues did not work when the plugin is activated.

Can you help me, please? Should i sent you a email with admin login?
Regards
Christian

btw. teh site is: http://www.dietanzschuhle.de plugin is now deactivated.

http://wordpress.org/plugins/simple-e-commerce-shopping-cart/