FS#1494 dwpage.php does not work after installing plugin diff and code2

After I've installed the plugin code2 and the diff plugin
dwpage.php doesn't insert pages into the wiki any longer.

www-data@deb:~/dokuwiki4/_test$ ./runtests.php
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head><title>DokuWiki Setup Error</title></head>
<body style="font-family: Arial, sans-serif">
<div style="width:60%; margin: auto; background-color: #fcc;
border: 1px solid #faa; padding: 0.5em 1em;">
<h1 style="font-size: 120%">DokuWiki Setup Error</h1>
<p>The datadir ('pages') does not exist, isn't accessible or writable.
You should check your config and permission settings.
Or maybe you want to <a href="install.php">run the
installer</a>?</p>
</div>
</body>
</html>www-data@deb:~/dokuwiki4/_test$

FS#1494 dwpage.php does not work after installing plugin diff and code2

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