At about 1:02 Robert Plant says something like “Let 'em”, that sounds more like he’s clearing his voice/puking.
What does he say?
Listening to the song now, I don’t hear anything like that around 1:02. 
Oops! Haha, that should be 2:38 (meaning 1:02 left in song).
Sometimes I am amazed I can tie my shoes.
Seems like it’s at 2:40 after the "open your arms, open your arms " bit (still trying to figure it out).
I’m gonna go with “Let it” and then there’s probably some slap-back echo reverb thing after that or it simply gets cut off. “Let my love come runnin’ in…Let it!”
I googled it. There are a bunch of sites with the lyrics. If mack is correct, here is the line:
"Open your arms, opens your arms,
Open your arms, baby, let my love come running in. "
I think I have the CD at home (yes, yes, I’m at work) and perhaps the lyrics, so later I can confirm (or not) if this is correct.
If you play it backwards, it says “Paul is dead.”
If it’s the part I think you’re talking about, it’s a sneeze that was kept in.
So off I went in search of a cite, and I’ll be damned if I can find a thing. Amazing- I wonder if this is just “common knowledge” I got in junior high or something.
FWIW, I can’t hear it as anything other than a sneeze now.
That’s what it sounds like to me, too.
I definitely can not hear a sneeze. Still sounds like “Let 'Em” with some weird recording error.
Nope, wrong band. Led Zep backmasking is always about praising Satan…or selling Cadillacs.
A third vote for this. It sounds pretty clear to me.