Bridging Faces Gives Error Message I have a problem with bridging the faces selected in the first picture.

When I click Bridge Faces this error message pops up:
Select at least two edge loops

What might cause the problem?
You are getting this error message twice:

Which means you are currently operating on two separate meshes.  Each mesh has a face selected so neither is able to complete the operation.
If you join the objects by selecting them in Object Mode and pressing Ctrl + J you will be able to run the operation normally.