I compared both in Opera Dragonfly and there's some weirdness going on which I don't have time to look at - may be something to do with you using a % margin on your #logo div which was getting affected by some other page element(s) BUT, the crux of the problem is that the page with the extra bit at the bottom of the logo was getting calculated to be 125px high, compared to only 122px high in your regular (correctly shown) page.
If you specify height:122px; for that div then it should fix it, but it may not automatically work if you simply add this to your css file - it may do and it's what I would try first but if that doesn't work it you could either add another section at the end of your css file:
#logo {height:122px;}
OR just change your actual html mark up for that div to read:
<div id=logo style="height:122px;">
Hope this helps.
Paul
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