Unhappy [Q] Plz help....:(

I m using Micromax A110 Canvas 2. I have installed [ROM] [JB 4.2.2] ---***Ultimate Galaxy V4 [New Updated]***--- Note 3 + S5 UI this rom. after installing the cell got started and i tried to install .apk file but its not getting installed. It is showing error as "APP NOT INSTALLED". All .apk files r not getting installed. plz help me what to do???