saving office 2003 file to share drive

[Lisa]

Recently my computer was upgraded from the microsoft office 2003 to
microsoft office 2007 , however when i try to save an excel file that was
created in office 2003 to my share drive i get this error message "
z\purchases.xls" cannot be found check your spelling or try a different path.
i have tried saving it to other paths and get the same message.
The operating system is window XP Professional.
Lisa

 

[dlw]

2007 is saving it with .xlsx instead of .xls