install problem white screen

hello community!

I tried to install openpublish-2.3-build441 an get a white screen.

I already installed Drupal 7 and openpublic -everything ok.

for openpublish i increased memorylimit... to

memory_limit =220M
max_execution_time=120
realpath_cache_size=2M
max_input_time=120

and still white screen. what can be the reason?

thanks for your help.