Can't move layers in Mac Acrobat 9 Pro

Question

I can't move layers in Acrobat 9 Pro, even though Adobe says it's possible. All that I get is a circle wih a slash at the cursor on clicking and holding the mouse, indicating that moving the layer up or down in the stack is not possible. No key presses help either. Four attempts to get a definitive answer from Adobe Support yield only that they said it was possible. They also admitted that even if you did move a layer, it would not affect how the layer objects display, ie. whether above or below other layer's objects!
Has anyone been successful in moving a layer?
Relatedly, one (Windows) respondent says she can "position" a new layer upon Layer Import, but the Mac dialog makes no mention of the layer stack, just the X-Y coordinates on the PDF page....
Thanks for any help or thoughts,
fss

Answer 1

Thanks guys for responding. I went through the usual steps of trashing preferences, shutting down the computer, going home, and drinking a beer. I got in this morning and booted her up, and now everything works just as it should.
No idea what it was. I'm positive that the tracks weren't locked, and I'm 95% sure that I was in arrow mode (I was selecting the layer right before trying to move it.)
I don't know what it was, but I hope it never happens again.
Thanks again,
Nathan