SSRS - Globals!RenderFormat.Name giving #Error for RDL files

Hi everyone,

In my SSRS 2008 R2 report I am using the following expression to set DynamicWidth property of a chart:

"PDF","26CM","10CM")

However, it does not change the size of the chart. I tried putting =Globals!RenderFormat.Name in a textbox to look up its value and it is giving me #Error, regardless of export format.

Any ideas?