Ok,
Thanks to tye getting me in the right direction. The page being called had a:

<input id="q" class="search inputsearch inputtext" name="q" type="sear
+ch" ...
[download]

This caused the HTML::Form module to have problems as "The following type names are used: "text", "password", "hidden", "textarea", "file", "image", "submit", "radio", "checkbox" and "option"." Which is the xhtml standard.

With a deeper look this doesn't appear to be a problem with HTML::Form though. Probably something syntactic with undefined values in my own code.