You are right ,

this is the last time ever i will install any thing from testing or devil,

for now, i will uninstall that app. , but i don't like to reflash my device as i dont have any problem in all device functions , except (ONLY)if i open that application which is showing that message.

i know the error may be exist in the system , but i will wait till the stable version of this app will be in extra , then i will install it. wish that will make it work again and fix the conflict with the system.

Thanks again for your help