Error when installing Update 11.0.16

Question

I am getting an error when I try to install update 11.0.16 for Acrobat Pro. At first I was trying to upgrade from 11.0.14 and the update would fail. So then I updated to 11.0.15 (which worked). However even on 11.0.15, when trying to install 11.0.16 on top of that the install gets just about all the way finished and then generates the following error:

"The instruction at 0x72ad4ac2 referenced memory at 0x72ad4ac2. The memory could not be written"

I've tried on two machines here and both are getting the same error. We are on Windows 8.1 pro

Ok to make it even stranger...I ran the update one more time to get the exact error text from the second machine and the install worked. I tried it again on the other machine and it worked there as well (this was after it failed on both 2-3 times). I went and tried it twice on a third machine and it got the same "memory could not be written update" error both times. Anyone else experience this or have any ideas as to what might be causing this / why it seems to work sporadically? thanks!