You mean python path...? I do not know... For hildon home widgets the desktop file should point to the corresponding "module" which has to be in /usr/lib/hildon-desktop/...
In the script I use "#!/usr/bin/env python" so I can execute it easier (shorter command) but it is not in the wiki... maybe I should delete that line and see if it is the path that causing issues... I cannot imagine how that could be an issue though...