SSRS 2008R2 Excel Dataset Parameter Adjusting

I would prepare a report which binds the data from a Excel file. I completed the connection. However I want to adjust a parameter into the dataset that binds the from Excel file. When I write following query it gives me the error below. Moreover, when I write the query without the parameter then it works. How Can I adapt a user-id parameter into my report?

When I write the following code then it works without error.

SELECT        `date`, `time`, `c-ip`, `cs-method`, `cs-uri-stem`, `cs-username`
FROM            `Tabelle1$report_2010`

SELECT        `date`, `time`, `c-ip`, `cs-method`, `cs-uri-stem`, `cs-username`
FROM            `Tabelle1$report_2010`
where  `cs-username`=@ParamUserName

The error message is here.

Error in WHERE clause near '@'.
Unable to parse query text.

KAdir