Where did you get the rpm from ? Its not in the standard repositories (OSS, non-OSS, Update). Nor is it in packman. Possibly from some Gnome repos ? Beware of packages whose spec files are incomplete for pulling in all required dependencies. You could contact the rpm packager !
Also, my apologies for asking the obvious (so no flames please), but I think it needs to be asked. … Since the error is telling you it can not find “PyGTK”, did you look to see if that was installed ? “Py” stands for python.
… so look for a package called ‘python-gtk’ and see if that is installed. … Again, I don’t use piviti, I’m simply reading the error message you posted.
To add to @oldcpu’s info: on messages like that, open Software Management, search for “pygtk” with the option “RPM provides” checked. That indeed brings up the package “python-gtk” in this case.