2000 to 2007 Compatibility
 

When opening an Excel 2000 workbook in Excel 2007, the data worksheets are
converted, but only the first of several charts (each in separate worksheets)
is converted successfully. Three of four charts have their background and
series points distorted (black). The referenced data, which is in
worksheets in the same workbook, is correct. The chart rendering is
distorted.

Suggestions?