(Sorry for the wait; my browser unexpectedly crashed after viewing someone else's blog.)
Without looking at the template itself I can't be positive, but it seems like the link to the Subscribe is potentially hard-coded into the Header template itself (provided that the navigation strip/bar is in the Header file and not in the Main Index or elsewhere).
If that is the case, then you will need to go into the Theme Editor and open up the header template and edit out the link and coding that goes with it.
The Subscribe page seems like it might be a template page as well or at the very least, another file included in with your theme. Are there any extra pages or files in your theme folder?