You didn’t leave me a return address, so I hope you see this response. I said I had an answer for you, but it’s taken many days to respond, and I apologize. It has been a difficult week in the salt mines. Deployments. Conference calls. Customers destroying network settings. Sales staff destroying demo software. It's crazy around here.
Anyway, the question was: how to hide a parameter in Reporting Services?
Go to the Report menu, select Report Parameters, and highlight the parameter you need to hide. The key is to clear the Prompt text box, and make sure to supply a default value. Reporting Services will no longer prompt the user to enter a value for the parameter. The parameter value can still be dynamic if there is a VB expression or a query to specify the default value.
To override the parameter at run time with a different value (perhaps by passing the new value in the query string when using URL access), then you may get the error “parameter is readonly and may not be modified”. Make sure to install SP1 for Reporting Services to fix this.
To determine the version of Reporting Services, go to the base URL for the report server (typically http://machinename/reportserver/. At the bottom of the browser page will be the version number:
Microsoft SQL Server Reporting Services Version 8.00.743.00 <- this is old
Microsoft SQL Server Reporting Services Version 8.00.878.00 <- this is SP1