The only thing I've found is that some sites don't support the iframe tag. I'm gonna consult with the webtech I know. *grumbles* does this link work for you?
It does for me, but I'm also logged into the google account right now. If it does work, then at least we can link to the calendar. I prefer to actually embed the damn thing so it's all spiffy and THERE, but if this functions for you, we've got a work-around until I consult on the < iframe > tag.