Center channel extractor... Help!

This happens because you have either ignored or dismissed the warning that comes up if you put processor-intensive effects into the effects rack, where this particular effect will show up as a red entry: What you should have seen and heeded was this:

Essentially, this is a 'process' effect and not meant to be applied in the Effects Rack at all; it's a process that you need to do with care, and independently. If you tell me that it shouldn't be allowed in the rack at all on that basis, I'd have to agree with you that almost certainly, it shouldn't be.