error during convert a BEAST MCC tree to a newick

[virologist]

Hi, @emmahodcroft @hxnx-sam

When I was trying to convert to the MCC tree to newick in R, I met an error like this.
The code is from here:

Warning message in matrix(tips, 2, length(tips)/2):
"data length [1027] is not a sub-multiple or multiple of the number of rows [2]"
Error in jj[[1]]: subscript out of bounds
Traceback:
1. MCC_to_NWK(mccName)

Do you know how to solve it?
Yan