Yes I tried to set the folder manually, but still the installer could not find any Archicad. I also tried to uninstall AC12 + JRE6 to prevent any problems vith versions (AC9 did not work with JRE6, only with JRE1.4.2) but it did not help.
Windows XP
AC12 EDU + Java RE 6 update 13
AC9 EDU + Java RE 1.4.2_17