Working in SSRS 2008R2, How can I dynamically select a drillthrough report name

See more:

SQL-Server-2008R2

I have customers that require unique summary billing statements. I have created a report project with a base report showing the following

SELECT Customerid     
      , name	AS Name
      , Report_Name
FROM dbo.customer_summary_Billing

I would like to be able to click on the report name, and have a action that will go to that report. When editing the Text Box properties, action tab, Go to report, expression for the report name = Fields!Report_Name.Value

I get an error: report cannot be complied. Verify the report name and that the report is in the current project. BUT IT IS?

Can anyone help me with this issue?
THANKS!

Sharon