As explained many times already, jetways can ONLY be excluded by another scenery. However, your message is not very clear: it seems to imply you have loading problem only when loading "from the cockpit" ?
Other buildings are an entirely and separate thing, so please, clarify exactly that is the problem.
Is this happening ONLY when loading "from the cockpit", is this happening ONLY with the PMDG 777 and, when you see jetway disappearing, to you *also* have everything else disappear, or the two events are unrelated and happens at separate times ?
When you see all buildings disappearing, do you still see the "Couatl powered products" menu under the FSX "Addons" menu ?