I was having this problem so I moved everything and downloaded the two files and I copyed the one file, but I was still getting a window that popped up when i ran the updater.
I couldn\'t see the name of the file it hung up on because all the words were blurred together from there being no background so I put libpng-cs.dll back in the main folder so i could see the background and the updater ran without any problems.
If anyone else has the same problem, moving libpng-cs.dll back may help.