Error in steac.sptree

[V-Z]

Hello, I loaded RAxML trees via ape::read.tree and when I run steac.sptree, I end up with error:

install.packages("http://faculty.franklin.uga.edu/lliu/sites/faculty.franklin.uga.edu.lliu/files/phybase_1.5.tar.gz", repos=NULL)
library(phybase)
raxml_best_trees <- read.tree(file="raxml_best_trees.nwk")
raxml_best_trees.speciesname <- raxml_best_trees[[1]]$tip.label
raxml_best_trees.taxaname <- raxml_best_trees.speciesname
raxml_best_trees.species.structure <- matrix(data=0, ncol=length(raxml_best_trees), nrow=length(raxml_best_trees))
diag(raxml_best_trees.species.structure) <- 1

raxml_best_trees.steac <- steac.sptree(trees=raxml_best_trees, speciesname=raxml_best_trees.speciesname, taxaname=raxml_best_trees.taxaname, outgroup="Oxalis-acetosella_S96", method="nj")
Error in read.tree.nodes(trees[i]) : 
  The number of comma in the tree string is wrong!

sessionInfo()
R version 3.3.2 (2016-10-31)
Platform: x86_64-suse-linux-gnu (64-bit)
Running under: openSUSE Tumbleweed
locale:
 [1] LC_CTYPE=cs_CZ.UTF-8          LC_NUMERIC=C                  LC_TIME=cs_CZ.UTF-8          
 [4] LC_COLLATE=cs_CZ.UTF-8        LC_MONETARY=cs_CZ.UTF-8       LC_MESSAGES=cs_CZ.UTF-8      
 [7] LC_PAPER=cs_CZ.UTF-8          LC_NAME=cs_CZ.UTF-8           LC_ADDRESS=cs_CZ.UTF-8       
[10] LC_TELEPHONE=cs_CZ.UTF-8      LC_MEASUREMENT=cs_CZ.UTF-8    LC_IDENTIFICATION=cs_CZ.UTF-8
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     
other attached packages:
[1] phybase_1.5  Matrix_1.2-9 ape_4.1      rkward_0.6.5
loaded via a namespace (and not attached):
[1] parallel_3.3.2  tools_3.3.2     nlme_3.1-131    grid_3.3.2      lattice_0.20-35

The input file seems to be fine as I can use it in another analysis, plot it, etc. I tried also with APE 3.5, but with same result.