Time Plug-in Problem...

Trying to set the date on some files as they are installed, because I don't want to uninstall them if they have been modified by the user.

I've installed the Time PI, read the readme, and I've put this line in my installer:

${time::SetFileTime} "$INSTDIR\Files\thisfile.txt" "$installDate" $installDate "$installDate" $9 

If I run the sample installer included with Time, it works fine.

Trying to figure out what's up. This is the error I get:
Invalid command: ${time::SetFileTime}
Error in macro COMPONENT_FILES on macroline 28
Error in script "C:\Projects\Inst\MyInstall.nsi" on line 180 -- aborting creation process

Never mind. Figured it out. Forgot to
!include Time.nsh