Vista Uninstall issue on 64bit system

[dantemw]

When running my NSIS installer on a 64bit version of vista I am making the following entry (plus others) via NSIS to the registry:

WriteRegStr HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Adobe Flash Player" UninstallString $SYSDIR\Macromed\Flash\uninstall_activeX.exe"

However this gets translated by NSIS to the following in the registry:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Adobe Flash Player UninstallString C:\windows\system32\macromed\flash\uninstall_activeX.exe

The $SYSDIR on Vista64 (and where NSIS put all of the files that I specfied for $SYSDIR) into the following directory:

C:\windows\sysWOW64\macromed\flash\

Obviously this breaks add/remove programs.
Can anyone be my guiding light here?

Thank you,
Michael