When I try to update ACR to 6.7...
I checked out the task manager first thing this morning and found no software running. The basic idea seemed valid so I did a re-start and opened PS first thing and navigated to Help/Updates. I tried to update just ACR and after running a few seconds, the dialog popped up prompting me to close PS. After doing so, ACR updated successfully. I followed the same procedure for PS and Bridge updates with the same positive results. Thanks for pointing me in the right direction.
Did you check it in task manager if any of these two processes are still running? It happens sometimes that no applications are listed but the process is still alive (which is the problem for itself). If "yes" terminate them and try again.
'Wish I didn't know now what I didn't know then.'