First, I didn't copy the old over the new, I copied the new over the old. So any new system type files were the current files after the merge. For the content, any content that was duplicated was the new stuff, so any content was either new or not from the old base install. Second, strictly as an academic exercise, I used my pristine CU1 and SR1 updated Poser and linked to the other folder's runtime, and after switching to the old runtime from within Poser, I was still getting the same types of errors. Thanks for the input, but unfortunately the linking versus copying issue didn't change things.