False failures can occur when the page targeted by a link has security that is dependent on web site state information previously entered by the user. This implies that some web site's web pages can not be exercised in random sequence, but must be invoked and forms filled in a particular sequence. Most every Internet agent, including Linkbot, assume that the web site under test is stateless. Linkbot sometimes returns failure results, like missing anchors, that are not really missing. Linkbot returns many failures, like missing alt text or missing image size attributes, that may not be considered important enough errors to fix.
Alt text is used by search engines as part of indexing a web page.
Image size attributes are used by browsers to render the web page more quickly. Some failures identified by Linkbot are browser dependent. But the latest browsers by Microsoft and Netscape will successfully interpret this malformed address. It is not always apparent what is the actual error being reported by Linkbot. Web pages are complicated.