[Qt-creator] Mercurial Woes on Windows 7 64 bit

[Robert Caldecott]

I am using the latest Qt SDK on Windows 7 64 bit and cannot get
Mercurial support to work at all.  I have hg.exe on my path but
whatever command I try from within Qt Creator I am greeted with the
same error:

22:02 Executing: "C:\Program Files (x86)\TortoiseHg\hg.exe" status
abort: There is no Mercurial repository here (.hg not found)!

The repository definitely exists and Mercurial works fine from a
command-prompt.  It's almost as if Creator is using the wrong working
directory when issuing the hg commands but there is no way to check
for sure.

Does anyone have any ideas?  It was working fine on XP/32 when I last tried it.

Regards.