It's impossible to help you without knowing which kind of jetways the scenery CURRENTLY has.
From your report, it seems instructions you found somewhere to install a GSX custom profile are outdated, perhaps the scenery has been updated in the meantime, so it doesn't have static jetways anymore but, what you are supposed to do in GSX depends on what they have been replaced with: if they now have standard CTRL+J jetway, you just follow the manual or the video tutorials here to replace standard jetways.
If they are SODE, instead, you cannot remove them from GSX, and you must remove their own SODE XML file instead.
