Get the attached error dialog 3 time when I try to do a Tools > Launch SSH Agent (Pageant).

Note, I seem to have 2 copies of it on my Windows 7 PC:
C:\>where pageant
c:\Program Files (x86)\putty\pageant.exe
C:\Program Files\TortoiseHg\Pageant.exe

I need SSH to clone a repository. Where can I find out more info on how to do this with SourceTree?

Olaf