• Supply the full URL to pmwiki -- http://example.com/pmwiki/pmwiki.php
• Make sure your analyse key doesn't have spaces in it
• Make sure the "analyze.php" script is readable (permissions)
• Consider enabling the Site Analyzer only on one page using per page customization.
• If you do not have a visible URL try Cookbook:RecipeCheck.

This page may have a more recent version on pmwiki.org: PmWiki:SiteAnalyzer, and a talk page: PmWiki:SiteAnalyzer-Talk.