DriveApp.getFolderById results in "you do not have permission" error
<p>I am having issues with the <em>getFolderById</em> function. I am the owner of the folder in question. The specific call is as follows.</p>

<pre><code>var folder = DriveApp.getFolderById('string_id_of_my_folder');
</code></pre>

<p>I am passing the long string of the ID of the folder inside the function. 
I ran the function inside the editor to make sure permissions have been turned on - and I'm not getting any errors.  </p>

<p>But when I try to run the function inside the spreadsheet, I get the following error message: <em>"You do not have permission to call getFolderById"</em>.</p>

<p>What am I doing wrong?</p>