OK found it.
http://tinyurl.com/yphxfa
Seems there is a known bug although I hadn't seen it before
the above post.
Take a copy of your project as it is now, even though it is
broken. Delete the CPD and XPJ files. Double click the HHP. Does
that open it?
Take a look at Opening Projects on my site for more
information.
Post back how you get on.
Is this a project you could copy to me? If it is, first let
me know the zipped size.
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