Named Data Ranges & Chart

I can't seem to get named data range into the source data of a chart, I try ="BHSUM","NGCSUM","LYNSUM","BLANKSUM" but anything I put in results in the source data being ={0,0,0,0}. How do I tell the chart to use the named data ranges for it's source data?

I've put =BHSUM, =NGCSUM, etc, into random cells to make sure all the formulas work, and they do.

I can get it to half work... When I put:

='Data Sheet 2'!BHSUM

It works, but Excel changes the code to =Courier.xls!BHSUM

So I try:

=('Data Sheet 2'!BHSUM,'Data Sheet 2'!TLCSUM)

And it gives me the error message "Your formula contains an invalid enternal reference to a worksheet."

I have a number of data ranges, BHSUM, TLCSUM, RTNSUM, MADSUM, LYNSUM, NGCSUM, BLANKSUM, and they all are valid working data ranges.