Encountered a very similar problem that OP is reporting today while installing Postgres 9.4.
It turns out that the password generator I was using has made a password that contains non-alphanumeric characters. (“^”) I believe was the culprit in this case. Removing that allowed the installation of Postgres 9.4 (Windows 64 bit) to complete.
Very easy fix once you’ve found it, but the error message that comes up is not descriptive, so in this case I didn’t notice at first what I was doing wrong.