SSRS 2008: error message saying my parameter doesn't exist but it clearly does?

Question

I have a report that has about 10 parameters and about 10 datasets and one datasource. I typed alot but I really need help so I figured I would try and provide as much info

Answer 1

I also had this issue, following the all the answers above deinetely helped.

The tricky one with mine is that the dataset was an SSAS dataset therefore it was hidden. I had to search the code for the parameter to see where it was used and thats where I found it.

To view hidden datasets right click the Datasets folder in the Report Data tab and tick the 'Show Hidden Datasets' box.