Which command are you using to plot?
If you're using the ACADE publish command, it shouldn't give this error at all because it won't try to plot a drawing that isn't in the project. Unless, of course, it's in the project but deleted elsewhere as noted by @Thomasbatson.
If you're using the ACAD publish command, simply don't include drawing 27 in the list.
If you're plotting from a .dsd file, it needs to be rebuilt in order to remove drawing 27 from the plot list.

Jim Seefeldt
Electrical Engineering Technician