I used limma to read and normalize An Agilent dataset, I did not apply the background correction on it which is:

y <- backgroundCorrect(x,method="normexp")#

Then I found another method which is nec(), neqc ():

y=nec(x, status=NULL, negctrl="negative", regular="regular", offset=16,robust=FALSE, detection.p="Detection")

But I received an error:

Error in normexp.fit.detection.p(x, detection.p) :
  Detection p values not found in the data.

Please any suggestion