So - this is a report that is using a SharePoint List for the data source, and I think you are saying that you have the possible options separated out for selection as a parameter, but the data returned isn't correct? If I recall correctly, with a report using a list for a data source, user passed in params don't work & you have to apply them as a filter to the returned data. Of course "does not work" is pretty vague - that could mean anything from "I don't get any data back" to "There is an error" or "The time-space continuum collapsed". So I'm guessing. :)