Warning: Cannot modify header information - headers already sent by
This is not a error, This is Warning,
Some hosting server showing this error due to server function. If you are facing this error you just need to follow these instraction.
1- Extract beetube.zip and find this file.
2- BeeTube--> extensions ---> class-tgm-plugin-activation.php
3- Open this file in text editor and remove from the first line.
4- And Remove this code from last line.
After to remove this save file and zip "beetube" folder and install again . It will work fine.