Thanks Bob! That was quick.
I re-traced my steps and as you just stated that's where I went wrong.
So I'm back on track now.
However, When I opened the "performance_dashboard_main.rd.",
I received this error in the Preview tab:
An error has occurred.....
Cannot read the next data row for the data set SESSION_CPU_WAIT_INFO.
Difference of two datetime colums caused overflow at runtime.