I just couldn't rename... file access denied by ashserv.exe.
I'm using, as you know, XP SP2+
Only with disabling avast and using Unlocker I could rename and copy the new files there.
Don't know... it works for me. I even tried on SP2 right now to make sure that it wasn't changed recently (I don't use SP2 personally), but it's OK. You can rename a running executable/DLL (even move to a different folder within a partition).
How can I test if it is working?
Well, if the error message appears for you (with the build 731), it should disappear now. If it doesn't... it's probably not necessary to use this version. No idea how the error can be "invoked" if it doesn't show by itself.