IE8 Table display problem

I'm having some display problems with IE8. Would someone have a look at http://resxrn.com/downloads#xrnIssues using IE8 and then look at the same url with Firefox?

With Firefox the table displays correctly, ie, the grid lines display. HOWEVER when viewed with IE8 they do not display. Any ideas how to get the table to display correctly in IE8?

Thanks for your time.
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JamesKB