i am using htacess file for increasing the max upload file size. When i write this code in .htacess file, got an error "The server encountered an internal error or misconfiguration and was unable to complete your request. "

php_value upload_max_filesize 6000M;
php_value post_max_size 6000M;
php_value max_execution_time 0;
php_value max_input_time 0;

can anyone help me why this error message is showing

thanks in advance....