Your php configuration is not proper.

Refer

YouTube Clone Server Requirements

safe_mode = off
register_globals = off
open_basedir = (no value)
output_buffering = on
upload_max_filesize = 200M (or more)
post_max_size = 200M (or more)
max_execution_time = 6000 (or more)
max_input_time = 6000 (or more)
memory_limit = 128M (or more)
display_errors = On
file_uploads = On
session.gc_maxlifetime = 14000 (or more)