Error in seq ...: wrong sign in "by" argument

Hi.
I'm using the package "seewave" to extract some features from audiofiles. One of the functions, "timer" on the backstage kind of create a plot and find, according to the parameters, where the sounds and the silences of the audio waves are. I'm trying to get how many sounds and silences are on all my files with a loop.

However, it is stopping on the 20% and I got the following:

Error in seq.default(1, n - msmooth[1], msmooth[1] - (msmooth[2] * msmooth[1]/100)) : wrong sign in 'by' argument

My code goes like so:

path <- 'directory'
audio_files <- dir(path, pattern='wav$')

sound_trials <- vector(mode = "list", length = length(audio_files)) #vector to store audio files
len_timer_trials <- vector(mode = "numeric", length = length(audio_files)) #vector to store number of sounds
pb <- txtProgressBar(min=1, max=length(audio_files), style=3) #progress bar
for (i in 1:length(audio_files))
{
  tmp <- readWave(paste('path', audio_files[i], sep='/')) #read audio files 
  sound_trials[[i]] <- timer(tmp, 44100, envt = 'abs', threshold = 15, msmoot = c(500,10)) #probably my parameters don't fit with all my files, having as a result that error?
  len_timer_trials[i] <- length(sound_trials[[i]]$s) #bring me how many sounds are detected for each file
  setTxtProgressBar(pb, i) #progress bar
}
close(pb) #progress bar
rm(pb) #remove progress bar

According to the documentation there is no "by" argument to set, so I'm not understanding this error. I think it might be that the number, but certainly i don't know. Some human help, please?
If it is something that is happening with a specific file, is it possible to add some sort of break to continue to my next file? All help is highly appreciated!