yeah sorry, it's either a bug in OSX, some very obscure reason why it's not working, or i am just actually dumb.
i right click 'get info' on a pd file, change the 'open with' application to pd 0.46.7, and then click on "change all" to make all pd files open in 0.46.7.....no error messages, all looks cool..
but now i just realised it is still opening pd files in the older 0.46.2
OSX10.10.3.... and no i'm not updating it again, cos every time i update OSX, i lose heaps of old stuff that i need cos mac doesn't care about backwards compatibility.
i'm so grateful Miller does!