Cron job returns "Undefined index: REQUEST_METHOD"

Hi,

I'm attempting to run a cron job using CodeIgniter 3.1.8. The cron job works fine locally from the Windows command line, but when I run it on a Linux server as a CPanel cron, I get this in the output (among various other session related warnings):

<h4>A PHP Error was encountered</h4>
<p>Severity: Notice</p>
<p>Message:  Undefined index: REQUEST_METHOD</p>
<p>Filename: core/Security.php</p>
<p>Line Number: 211</p>

Would be grateful for any help...