I want to plot several samples at once I have run this command

plotTranscripts('TraesCS1B02G048400', bg_chrX, samples=c('G1', 'G2', 'G3', 'G4'),meas='FPKM', colorby='transcript')

The error got is

Error in seq.default(min(gtrans$start), max(gtrans$end), by = 1) :

'from' must be a finite number

In addition: Warning messages:

1: In min(gtrans$start) : no non-missing arguments to min; returning Inf

2: In max(gtrans$end) : no non-missing arguments to max; returning -Inf