<p>Moodle may have a variety of problems with safe mode on, not least is that
   it probably won't be allowed to create new files.</p>

<p>Safe mode is usually only enabled by paranoid public web hosts, so you may have
   to just find a new web hosting company for your Moodle site.</p>

<p>You can try continuing the install if you like, but expect a few problems later on.</p>