Yeah-- this is an example of knitting lingo. Knitting even, just means knitting plain-- as zkimom said, no increases, no decreases, no nothin'.
They are having you knit 1 round even/plain between increase rows because otherwise you'd have a very wide thumb gore/gussett-- this way, it'll be more gradual and work and look better. Do you notice that each increase round has 2 more sts inbetween the 2 new increase sts? That's what I was talking about in that other thread.
I'm looking over this, thinking what might also come up for you
. . .
When it says cast on 1 st over the 11sts on the holder, just loop the yarn round the needle for that. It's just going to pull things together a bit for the hand of the mitten, which is what you're going to be continuing at that point.
It says to "continue knitting ever rnd until piece measures 8" from cuff or desire length." You want to leave about an inch or an inch and a 1/2 from the total length of the mitten because you still have 8 rnds to go. So if your hand measures 7" from the wrist (where the cuff ends) to the tip of your middle finger, then only knit for 5 and 1/2 or 6 inches, instead of the 8. You can actually do this quite accurately, because by the time you're halfway up the fingers, you'll have plenty of room to measure-- just take a ruler and see how much 8 or your rows measure-- let's say it's one and 1/4 inches. Then that's what you want to leave room for those last 8 rows. Same with the thumb-- you have 3 rounds left after their suggested 2". So measure the thumb length and subtract what 3 rnd will equal and go from there.