You may have tried setting ini variable with php.ini file in the root. You may have also tried placing the php.ini file in the wp-admin folder. But what worked for me is placing a php.ini file in the wp-content/plugins/wp-filebase folder with the following 3 line. Modify for your needs of course.
upload_max_filesize = 256M
post_max_size = 256M
max_execution_time = 30000
Good luck.
-jeff