x64 support

Another question: does NSIS have built-in support for 64-bit Windows in regards to the variables $WINDIR, $SYSDIR, etc.?

Not yet.

How far in to the future do you see before that is implemented?

No idea. You can call special APIs using the System plug-in for now.

Ok, I'll look at that. I've been browsing around MSDN a little and found this http://msdn.microsoft.com/library/de...plications.asp
Wasn't sure the calls you're making would get redirected like this is explaining.