I'm trying to remember the name of a show or movie? I used to watch, I think in the late 90's. It was on when Sweet Valley High was on.

It was about a girl and her family. Her name was Cathy, or Kathy and they were stuck in these dimensions. In the only episode I remember they were in a town that had made themselves immortal but had rendered themselves impotent as a result and they wanted Cathy and the guy she was with (tall black man) to either make children for them, or they were going to give her a shot that would make her immortal too. She had an accent I think, Australian or British?

If anyone knows what I'm talking about, I'm starting to think I made it up.