alpha,
Yes I use the same tweak for checking missing GUID files but because there is no know way to determine the object that 32 character number refers to, at least from everything I can find on the web and from asking others, let me suggest you do like I did and simply change the MissingLibraryAlert=1 to a 0 and let the sim load without pointing out these so called errors. At this time it cannot be determined why they appear with the alert set to 1. I suspect that there are some library scenery objects from an unknown library being used in our scenery but no one has determined for sure that this is the case.
By the way your post of the number is not correct as the format is 8 characters, a space 4 characters, a space 4 characters, a space 4 characters, a space then 12 characters. Should be a total of 32 characters and you are showing 33 in your post.