Can't save "Error Display" setting in admin about wp-scss HOT 1 CLOSED

Some more details:

Error Display:
the page doesn't display "Print to Log", but in the db options table, it's set to "log". However no logfile appears (I'm not sure where it's supposed to be created. In the plugin's folder?)

"Show to logged in users" works fine. I thought I tested it earlier, apparently not. So just an issue with displayed the 3rd option.

fwrite error:

• I downgraded from php 5.6 to 5.5 - no change.
• I have been getting the error while compiling a full theme with many scss files (Genesis Sandbox + Compass libs). So I tested a blank theme with a single 5 line scss file. There's no error compiling the basic scss.
• based on this page: https://www.drupal.org/node/1064690 - I inserted the code below near the top of wp-scss.php:

if (!defined('STDERR'))
    define('STDERR', fopen('php://stderr', 'w'));

This works - no error is displayed. Admittedly it's a very hackish solution. I don't know how STDERR can be undefined. I'm not using shared hosting (using a server config from serverpilot, which is normally pretty reliable). Still, I guess my "fix" isn't actually harmful to anyone, and might resolve issues for others with certain hosting environments (whatever the root cause may be).

Edit: Technically I shouldn't have closed this, since the error display issue still exists, although it's minor.

from wp-scss.