The main difference is that DIV is interpreted as table. However, this should be a Ms error.
Add the following code to your webconfig:
<! --, Rob Eberhardt-http://slingfive.com/demos/browserCaps/ -->
<Browsercaps>
<! -- Gecko based browsers (Netscape 6 +, Mozilla/Firebird,...) // -->
<Case match = "^ Mozilla/5/. 0/([^)] */) (Gecko/[-/d] + )? (? 'Type' [^ // D] *) ([/d] *)/(? 'Version '(? 'Major'/d + )(? 'Minor'/./d + )(? 'Letters '/W *). * ">
Browser = Gecko
Type =$ {type}
Frames = true
Tables = true
Cookies = true
Javascript = true
Javaapplets = true
ECS mascriptversion = 1.5
W3cdomversion = 1.0
Css1 = true
Css2 = true
Xml = true
Tagwriter = system. Web. UI. htmltextwriter
<Case match = "rv :(? 'Version '(? 'Major'/d + )(? 'Minor'/./d + )(? 'Letters '/W *) ">
Version =$ {version}
Majorversion =$ {major}
Minorversion =$ {minor}
<Case match = "^ B" with = "$ {letters}">
Beta = true
</Case>
</Case>
</Case>
<! -- Applewebkit based browsers (Safari...) // -->
<Case match = "applewebkit /(? 'Version '(? 'Major'/d )(? 'Minor'/d + )(? 'Letters '/W *) ">
Browser = applewebkit
Version =$ {version}
Majorversion =$ {major}
Minorversion = 0. $ {minor}
Frames = true
Tables = true
Cookies = true
Javascript = true
Javaapplets = true
ECS mascriptversion = 1.5
W3cdomversion = 1.0
Css1 = true
Css2 = true
Xml = true
Tagwriter = system. Web. UI. htmltextwriter
<Case match = "applewebkit /(? 'Version '(? 'Major'/d )(? 'Minor'/d + )(? 'Letters '/W *) (/(khtml, like Gecko /))? (? 'Type' [^ // D] *)/. * $ ">
Type =$ {type}
</Case>
</Case>
<! -- Konqueror // -->
<Case match = "Konqueror /(? 'Version '(? 'Major'/d + )(? 'Minor'/./d + )(? 'Letters ');/W *(? 'Platform' [^/)] *) ">
Browser = Konqueror
Version =$ {version}
Majorversion =$ {major}
Minorversion =$ {minor}
Platform =$ {platform}
Type = Konqueror
Frames = true
Tables = true
Cookies = true
Javascript = true
Javaapplets = true
ECS mascriptversion = 1.5
W3cdomversion = 1.0
Css1 = true
Css2 = true
Xml = true
Tagwriter = system. Web. UI. htmltextwriter
</Case>
</Browsercaps>