Do you have duplicate x-values? Try to hook up an idicator to the currently unwired error_out terminal for the "spline interpolant vi" (located right before the spline interpolation.vi.)
You'll get an error -20049 if there are duplicate x-values, which later magically propagate to an error -2002 in the spline interpolation. Error -2002 is somehow misleading, because it is NOT the first error in the chain. Correctly programmed, the spline interpolation should be bypassed if the earlier interpolant returns an error.
