Error in mutate

Avis : Error in mutate: ℹ In argument: `Area_Iso = corrected_area * isotopologue`.
Caused by error in `corrected_area * isotopologue`:
! argument non numérique pour un opérateur binaire
  110: <Anonymous>
  109: signalCondition
  108: signal_abort
  107: abort
  106: h
  105: .handleSimpleError
  104: eval
  103: mask$eval_all_mutate
  102: mutate_col
  100: mutate_cols
   99: mutate.data.frame
   98: mutate
   97: group_by
   96: mutate
   95: mutate
   94: data.frame
   93: %>%
   92: eventReactiveValueFunc [/home/rifa/repository/graphstats/R/mod_inputs_isot.R#352]
   48: mergetable
   47: observe [/home/rifa/repository/graphstats/R/mod_inputs_isot.R#406]
   46: <observer>
    3: runApp
    2: print.shiny.appobj
    1: <Anonymous>