we already discussed this issue on our IRC channel (#gnome-debian) some weeks ago.
This code prevents hamster-applet to startup correctly:

        if os.path.realpath(__file__).startswith(defs.PYTHONDIR):
            data_dir = os.path.join(defs.DATA_DIR, "hamster-applet")
        else:
            data_dir = os.path.realpath(os.path.join(os.path.dirname(__file__), '..', 'data'))

it would be nice to have it fixed somehow, I don't know which way you wanna follow to adjust it. We fixed it by totally removing the path checks:

-        if os.path.realpath(__file__).startswith(defs.PYTHONDIR):
-            data_dir = os.path.join(defs.DATA_DIR, "hamster-applet")
-        else:
-            data_dir = os.path.realpath(os.path.join(os.path.dirname(__file__), '..', 'data'))
+        data_dir = os.path.join(defs.DATA_DIR, "hamster-applet")
+

I'm CCing Joss so that he can give you some hints if needed.