pylink module name conflict (Eyelink)
It looks as though there is a package called 'pylink' at the PyPi repository (https://pypi.python.org/pypi/PyLink). Coincidentally, there is also a module called 'pylink' in the SR Research developers kit, which pygaze depends on for communicating with an Eyelink machine.
I have both of these installed. When I try to use pygaze with an Eyelink, it preferentially imports the 'wrong' pylink. For now I have just uninstalled the other pylink, as it doesn't seem to be necessary for anything I am doing at the moment (I probably just installed it myself by mistake while looking for the SR Research pylink).
So it seems the problem is solved. But just in case it turns out that I actually installed the other pylink for a reason, is there a good way of temporarily instructing Python to change its preferences about where to import from, so that I can tell an experiment script to make sure the right pylink is imported?