Open XLS on Excel 2008 Mac   

I am using Mac 10.4.11
Office 12.1.0

When I try to open an xls file Excel does not open.  It opens all new xlsx
files no problem.
It seems as though it begins to open the xls file with the  little open
screen but then nothing. I have tried opening through
File->open
File->recent
Drag over Excel Icon

Any help greatly appreciated.

date: Tue, 27 May 2008 11:01:09 -0700   author:   MagañaVicente