I found other discussions that indicate that this problem can be resolved by extracting the MSI files from the executable wrapper and running them directly (http://www.myitforum.com/forums/tm.aspx?high=&m=215451&mpage=1). I did that, running the x86 MSI with this setting from SCCM (msiexec /i jre1.6.0_20.msi /quiet /norestart ADDLOCAL=ALL IEXPLORER=1 NETSCAPE=1 MOZILLA=1 REBOOT=Suppress JAVAUPDATE=0). It worked great. x86 Java installed just fine without errors on my x64 Win 7 machines where it was failing when I tried to install from the exe. It's a pain to add the extra step, but at least it worked for me.