Ideas
This is a new problem for me. I had not tried to save a lot until recently (November) and I got that same server error as listed below. I've removed every single mod and script I use, and uninstalled and reinstalled my game in a different directory path.
I started the vanilla game and tried to save an existing sims house, and it worked. BUT, when I deleted a sims lot and created my own architecture on that lot and tried to export the lot, it gave me the server error. I uninstalled and reinstalled again, and got the SAME PROBLEM. It does this for the blank lots in newcrest also. Any and every lot is affected by this issue.
It is not due to any mods or a corrupted game because this happens with a CLEAN VANILLA installation. It is really frustrating because I love to build.
I read that it is a bug after the burglar upfate. I will look through the game options and disable the burgler a=to see if that helps.
I've included my dxdiag.