Here is the recorded action:

SwfWindow("PRISM G2").SwfToolbar("_ProjectManagerWindow_Toolbars").PerformToolAction tbmgrRibbonTab, tbmgrClick, "Cost Management (Mar '11):Cost", "Cost Control Accounts"

When running the line, it errors out.  Error:

Object reference not set to an instance of an object.

Line (82): "SwfWindow("PRISM G2").SwfToolbar("_ProjectManagerWindow_Toolbars").PerformToolAction tbmgrRibbonTab, tbmgrClick, "Cost Management (Mar '11):Cost", "Cost Control Accounts"".