Umm... don't use 'fieldset'? (:-))
From the first entry I googled up:
"HTML <fieldset> tag
Definition and Usage
The fieldset element draws a box
around its containing elements"
Did you actually want a 'frameset', maybe?
-- Pete --
[BTW, I cut & pasted your code snippet, and ran it through 'tidy',
to the empty 'legend', and removed it! Still got
the box in firefox, though]
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