dbo.DelimitedSplit8K is the user-defined function described in the article I linked to in my second reply. It's only valid in MS SQL though.

It's basically a bit of code that will convert the parameters into the correct format:

The parameters are being passed to the report query as 'Brass, Bronze' - you need something to convert it into 'Brass', 'Bronze'

This link might help you further:

http://social.msdn.microsoft.com/Forums/uk/sqlreportingservices/thread/31c1ab35-2b78-4d30-9fec-7c95e1cd7d0a

Cheers

Gaz