different grid lines in IE6 and FF

Hi,

we have following problem with IE8 ans up and safari too.

The grids of our tables are in Firefox very nice but in the other browsers we must put any cell and set the parameter for the table layout over css in it.

you can see it here [url=http://www.orthocentrum-hamburg.com/index.php?option=com_k2&view=item&id=51:unikondylärer-teilersatz&Itemid=29]example[/url]

It is possible to change the addon.css or any other to make visible the grids in IE and Safari,

we have more the 100 Tables in our presentation.

best regards
michael:sick: