Pinpointe has a special custom field/variable that can be used to display error messages to your contacts when they are using web forms. For internal error pages that are stored in Pinpointe internally, you can use the custom field %%GLOBAL_Errors%% in order to display these error messages to your contact...
For external error pages where you "use existing URL" for your error pages, Pinpointe passes a special variable in the URL called Errors.
HTML code for an error page might look something like this:
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<html> <head><title>Error has occurred</title></head>
<body>
The following error has been returned: <?php print $_GET['Errors']; ?>
</body>
</html>
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