The ReportViewerPrinter setting defines the Printer Driver (and therefore also the .WPD file) used when reports are printed to the screen using the Report Viewer. ReportViewerPrinter should be set to the Printer Number configured with the desired printer drivers. If set to 0 (the default) or to an invalid printer number the printer specified in the Printer Name report parameter for the current report is used. If set to -1, an internal screen driver is used and the Report Viewer Print Button is disabled.
ReportViewerPrinter=# - where # is any Printer number, 0 or -1