Wow, my first thought is that anytime you change servers links get broken.
I am guessing that the reason your files are read only is because of this factor.
Even though it sounds like all of your settings in tools>options>system properties>file locations
seem based on what you are describing to be the same, I would still go in there and create new links to the new server.
Also, what happens if you go into windows explorer and RC on these model files and select properties, then uncheck the read only.
Would they then work?
I tried to do that with the full folder - it let me un check the box, and asked if I would like it to apply to all folders & sub folder.
I said yes - it looked like it was working - but no change.
I will try it on single files - but man, there's 10,000 of them.
Not sure how your macro skills are, but this sure looks like a good place for one.