Data Validation no longer works after save

Hi all,
I am using the following formula for data validation in Excel 2007.
=AND($L$8:L62<>"Yes",L64:$L$269<>"Yes")
The above formula would be in cell L63.
The formula in cell L64 would be: =AND($L$8:L63<>"Yes",L65:$L$269<>"Yes") etc. etc.
I have the data in 260 consecutive cells in one column.
Basically it is to stop any more than one entry of "Yes" in the cells L8:L269 if there is already one cell with the word "Yes" in it.
If the word "Yes" is cleared from the initial cell, you are allowed to enter the word "Yes" in any one of the 261 cells.
This all works fine and is exactly as I require.
However, once I save and close the document and try to reopen it again, none of the settings work even though the formulas are still there and intact.
I have to click on the validation for the first cell and then tick on "apply these changes to all other cells with the same settings" and then OK to make it all work again.
Even if I save the file with the box ticked, when I re-open the spreadsheet the box is blank.
Is there something I need to do so that the validation works all the time?
I apologize for being so long winded in the explanation but I would be grateful for any solution.
Thank You
Regards,
Maltese Falcon