Problem for execute two buttons AddIns at the same time in ArcMap

Hi, I am working on a AddIn button for ArcMap to Export and Import a ShapeFile, my problem is: when I want execute the two buttons in the same time, ArcMap generate the next error “ArcGIS Desktop encountered a serious application error and can not continue” and the Windows of ArcMap closed immediately.

Thanks¡¡¡¡¡¡