Common snippet error messages and their meaning
From MODx Wiki
Unknown(): open_basedir restriction in effect. File(/something/somefile.inc.php) is not within the allowed path(s)
Usually this means that files are included in the snippet without defining the full path to the file.
So instead of: include_once('something/somefile.inc.php');
Use: include_once($modx->config['base_path'].'assets/snippets/mysnippet/something/somefile.inc.php');
Parse error, unexpected '<' in /manager/includes/document.parser.class.inc.php(705) : eval()'d code on line 1
This is one of the most common parse errors in pre 0.9.5 releases. There is a <? or <?php in the first line of the snippet code which must be removed. Also, look at the end of the snippet code and ensure it does not contain ?>. In 0.9.5+ <?php tag is detected in the snippet code and dealt with. Developers often put <?php to the start of the snippet code to get syntax coloring working in their text editors and that's the most common reason why you may see some snippets having them.
Snippet includes php scripts that are not parsed by php at all
This is probably because your server environment does not support short php open tags. Look at the top of the file that is not parsed for <? and change that to <?php
Parse error, "Execution of a query to the database failed - You have an error in your SQL syntax near '[[..."
When nesting snippets (for example: [[Wayfinder? &startId=`[[UltimateParent]]`]] ) one or the other must be uncached [! !] (example: [!Wayfinder? &startId=`[[UltimateParent]]`!] ). Embedded tags of the same type do not work until 0.9.7.
