Help with Doid Incredible Sence Facebook app

[Guest robman51]

This morning i was deleting some app that i thought i wouldn't need using root uninstaller and i accidentally deleted Facebook for Htc Sence. it messed up all my contacts. how do i go about installing it back on my phone. i tried downloading the apk. file and pushing it to system/app/ location. i did but it sayed not installed when i tried to install it from astro file manager. HELP