If I had to guess I would say the most likely spot would be the banjo bolt that connects the "cooler" or trumpet line to the power steering pump.
edit- I had to correct that. From the PS pump to the rack is the line I was thinking of.. it is the pressurized line that is not listed as being replaced in this DIY. I don't think that line will have very much play in it.
#5 in this photo-
http://www.realoem.com/bmw/showparts...50&hg=32&fg=20