edit htaccess to publish larger files

I am trying to use Tierra Audio Playlist Manager to post mp3 files, to allow playback on our site.
The Tierra page gives me this error message:
php_value post_max_size 100M (or more if needed)
php_value upload_max_filesize 105M (or more if needed)
php_value max_execution_time 500 (or longer if needed)

I try to edit the htaccess, but it 500 crashes the site. I’ve tried writing Tierra, but have not gotten an answer.
Can anyone help me with this?
Phil