May I know how to solve the error below?

define_clusters_by_cutting_tree.pl -R fruit_DE_Unigenes.matrix.RData --Ptree 60
CMD: Rscript __tmp_define_clusters.R
Loading required package: BiocGenerics
Loading required package: parallel

Attaching package: ‘BiocGenerics’

The following objects are masked from ‘package:parallel’:

    clusterApply, clusterApplyLB, clusterCall, clusterEvalQ,
    clusterExport, clusterMap, parApply, parCapply, parLapply,
    parLapplyLB, parRapply, parSapply, parSapplyLB

The following objects are masked from ‘package:stats’:

    IQR, mad, sd, var, xtabs

The following objects are masked from ‘package:base’:

    anyDuplicated, append, as.data.frame, basename, cbind, colnames,
    dirname, do.call, duplicated, eval, evalq, Filter, Find, get, grep,
    grepl, intersect, is.unsorted, lapply, Map, mapply, match, mget,
    order, paste, pmax, pmax.int, pmin, pmin.int, Position, rank,
    rbind, Reduce, rownames, sapply, setdiff, sort, table, tapply,
    union, unique, unsplit, which, which.max, which.min

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Attaching package: ‘fastcluster’

The following object is masked from ‘package:stats’:

    hclust

Error in UseMethod("as.dendrogram") : 
  no applicable method for 'as.dendrogram' applied to an object of class "NULL"
Calls: heatmap.3 -> as.dendrogram
Execution halted
Error, cmd Rscript __tmp_define_clusters.R died with ret 256 at /home/cbr01/anaconda3/envs/wee_bfx/bin/define_clusters_by_cutting_tree.pl line 213