After some googling I was unable to find an exact answer to my issue,
so here's my post:

We have a file structure on our servers which involves a folder that
contains hundreds of info files about particular things that all look
like this format: .a.b.c(.old/.new)

If I run the following command:

rsync user@node::filefolder

I get a directory list AOK -- it lists out all the hundreds and
hundreds of files.

If I run the following command:

rsync user@node::filefolder/.*

I get error in rsync protocol data stream (code 12)

If I choose a wildcard which contains only a few files:

rsync user@node::filefolder/.8.*

It works and lists fine. But if I choose a wildcard which contains a
LOT of files:

rsync user@node::filefolder/.7.*

I get error in rsync protocol data stream (code 12)

What I don't understand is why using the wildcard creates this problem.
Unfortunately, there are other files in this folder which I do not
want to rsync around, and removing those files from this folder (or
moving the files I want to a different folder) is also not really an
option as it would require some re-engineering of our software.

Any thoughts? All the computers involved have significant resources
(processor/ram/hd), so I am not thinking it is a resource issue... I am
dealing with approximately 5500 files with the .a.b.c(.old/.new)
format... there are 4024 files with .7 as their prefix. The entire
folder (obviously) has more files in it, which total about 5600.

Any ideas?

Obviously I'm trying to SYNC files, not just list them... I get the
same errors when trying to sync these specified files.