[SM-PLUGINS] Compatibility plugin error with PHP

[Alex <mys...@gm...>]

Hi,

I'm using the compatibility plugin with squirrelmail v1.4.22 and just
noticed I'm receiving the following in error_log:

[Mon Jun 03 15:26:41.933687 2013] [:error] [pid 1194] [client
209.33.37.13:54554] PHP Warning:  Creating default object from empty
value in /usr/share/squirrelmail/plugins/compatibility/includes/1.5.2/global.php
on line 898, referer:
https://mail.hotel.bestwestern.com/webmail/src/right_main.php?sort=1&startMessage=16&mailbox=INBOX

Is this a known issue? Is there something I can do to fix this? Here
are the lines it's complaining about:

   896           $rfc822_header->encoding = $special_encoding;
   897        else
   898           $rfc822_header->encoding = '8bit';
   899        if ($default_charset)
   900           $content_type->properties['charset']=$default_charset;

I believe I'm using the most recent version. Is there a configuration
option I'm missing?

Thanks,
Alex