Default [Q] Unable to install falcon pro on Nexus5 4.4.2 ART or Dalvik runtime, how do i fix?

hi all,

i am unable to install falcon pro twitter client on my nexus5 4.4.2 on any of the run time environments (ART or Dalvik)
i have also enabled 3rd party app installation option in the settings

any suggestions or did i miss something obvious.

or does it (falcon pro) support N5 devices?