How to store only first mode result in aanma.pdbs()/nma.pdbs()?

I have been trying to store only first mode results of aanma.pdbs() or nma.pdbs() using subspace option. However, I am getting an error as 'Warning in mylapply(1:nrow(inds), function(row) { : all scheduled cores encountered errors in user code Error in tmp.rmsip$rmsip : $ operator is invalid for atomic vectors'

How to store only first mode results if subspace = 1 is throwing this error.