Grasshopper, heres the navigation string from one of my linked subreports ('ShowVRDetail' with parameter 'ApptID') ....

[font="Verdana"]="void(window.open('http://reports/ReportServer?" & Globals!ReportFolder & "%2fShowVRDetail&rs:Command=Render&ApptID=" & Fields!AppointmentID.Value & "'))"[/font]

Note: this opens the subreport in a new pop-up window, I prefer that than the user having to hit the back key to go back to the main report - this way they can open as many subreports as they like in new ie windows.

Use the Globals.ReportFolder global so your subreport runs from any directory (i.e. reports/Test and reports/Production).

If you want to call different reports depending on the param the user picked you can go...

[font="Verdana"]="void(window.open('http://reports/ReportServer?" & Globals!ReportFolder & "%2f" & IIF(MyParam = value, "Report1","Report2") & "&rs:Command=Render&ApptID=" & Fields!AppointmentID.Value & "'))"[/font]

That should work (haven't tried it myself).

Hope that helps