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

Had the same problem. Check the Parameters tab of the Dataset Properties and click the expression (fx) button. The parameters don't seem to refresh automatically here, one of my parameters still had uppercase instead of lowercase spelling