This sounds largely like a PHP/Apache configuration issue rather than an OJS question, so you may find better results with a forum such as StackExchange.
Aside from your PHP version being pretty old, I’m wondering about the lack of a trailing slash on the RewriteBase directive.
Additionally, note that for Apache 2.4 you may need %{DOCUMENT_ROOT}%{REQUEST_URI} instead of %{REQUEST_FILENAME}, which was the default in Apache 2.2.