did you install any Bitnami module on top of that WAMP stack previously? Please note that the rest of modules will use the same user / password configuration you used when installing the first one. This information is stored in the
installdir/properties.ini file, can you take a look at it?
Regarding the installation error, the installer generated a log file inside the %TEMP% folder of your computer, can you share it with us? The name of that file is