With @PBulls' answer, I installed the older X13 binary. While I agree that it's not a proper fix, it gets me past the first hurdle of migrating the application to the newer server. The steps were:

p1 = "http://cran.r-project.org/src/contrib/Archive/x13binary/x13binary_1.1.39-2.tar.gz" 
install.packages(p1, repos=NULL, type="source") 
library("x13binary") 
library("seasonal")