I installed the Android WhatsApp app on my Blackberry but some features don't work I downloaded an android version of WhatsApp Messenger on my Blackberry Z 10 but I am unable to send any audio or video files. Why? What can I do about it?
WhatsApp announced their decision that the WhatsApp application will no longer support BlackBerry OS and BlackBerry 10 devices, among other devices, by the end of 2016 June 30th, now updated to December 31, 2017. BlackBerry devices powered by Android such as BlackBerry PRIV and BlackBerry DTEK50 will continue to be supported.


  Note: Because we will no longer actively develop for these platforms,
  some features may stop functioning at any time.


So let's assume that sending media files is no longer supported.

If you would like more specific information on what specific WhatsApp functionality will remain on BlackBerry OS and BlackBerry 10 devices, as well as other devices for which WhatsApp has decided to end support, please contact WhatsApp here.

Further reading here.