The nav issue is a bp bug.
Might want to look at this patch:
On Wed, Oct 19, 2011 at 4:42 PM, Chaz Cheadle <email@example.com>
I think there are -moz-... attributes for border radius that are compatible with IE7.
On Wed, Oct 19, 2011 at 4:40 PM, Nick Perez <firstname.lastname@example.org>
First of all, old IE (pre-9) doesn't support any form of border radius beyond hacks. I think the messed up colors are due to the background of nav li a - url(../images/60pc_black.png). This could be changed to #676767 and it looks pretty much identical.
I think the list issue vaguely has something to do with the display property in #nav li , but I haven't had a lot of time to look into it . I'll have more info soon if noone else does..--
-- Nick Perez