<br />
<b>Fatal error</b>:  Uncaught ValueError: mb_substitute_character(): Argument #1 ($substitute_character) must be &quot;none&quot;, &quot;long&quot;, &quot;entity&quot; or a valid codepoint in /home/prosiding/web/proceedings.upi.edu/public_html/lib/pkp/classes/core/PKPString.inc.php:71
Stack trace:
#0 /home/prosiding/web/proceedings.upi.edu/public_html/lib/pkp/classes/core/PKPString.inc.php(71): mb_substitute_character()
#1 /home/prosiding/web/proceedings.upi.edu/public_html/lib/pkp/classes/core/PKPApplication.inc.php(165): PKPString::init()
#2 /home/prosiding/web/proceedings.upi.edu/public_html/classes/core/Application.inc.php(36): PKPApplication-&gt;__construct()
#3 /home/prosiding/web/proceedings.upi.edu/public_html/lib/pkp/includes/bootstrap.inc.php(74): Application-&gt;__construct()
#4 /home/prosiding/web/proceedings.upi.edu/public_html/index.php(71): require('...')
#5 {main}
  thrown in <b>/home/prosiding/web/proceedings.upi.edu/public_html/lib/pkp/classes/core/PKPString.inc.php</b> on line <b>71</b><br />