Converting from 2003 to 2007

I have a complex spreadsheet that has 2 charts in it. I didn't create them
as I am not great with charts. However, I have been responsible for updating
them for the last year. We converted from 2003 to 2007 today and for some
reason the charts are blank. They appear to be there and I can get to the
format options, but they are just white... Help.
All I did was open the 2003 file with 2007. I opened it from a machine that
still has 2003 and the chart looks fine...