missing quotes
diff --git a/system/plugins/captcha_pi.php b/system/plugins/captcha_pi.php
index 7aa31ef..2c82f70 100644
--- a/system/plugins/captcha_pi.php
+++ b/system/plugins/captcha_pi.php
@@ -245,7 +245,7 @@
 	// -----------------------------------

 			

 	// PHP.net recommends imagecreatetruecolor(), but it isn't always available

-	if (function_exists(imagecreatetruecolor))

+	if (function_exists('imagecreatetruecolor'))

 	{

 		$im = imagecreatetruecolor($img_width, $img_height);

 	}