Dynamic Chart with an OFFSET that has a Dynamic reference gives error

Hello,

I'm trying to create a chart that pulls the data for the last 6 months and dynamically updates this based on what month I choose from a dropdown. The formula for the named range look like this:

Data points: OFFSET(INDEX(Values!$C$7:$XFD$7,,MATCH('Charts'!D12,Values!$C$3:$XFD$3,0)),0,0,1,-6). Index here is going to find the cell reference for the value corresponding to the date chosen from a drop-down.

If I don't use Index and just give the OFFSET a static reference cell, then the formula works in a chart. Otherwise, the chart gives an error and tells me that the formula is invalid.

Anyone know how to get around this? I'm suspecting it has something to do with how INDEX relays the reference information to the OFFSET function.

By the way, I have followed the instructions from here to create the charts, including the named ranges procedure: http://chandoo.org/wp/2009/10/15/dyn...t-data-series/

Thanks!