gfci.discrete null pointer exception error

[kingfish777]

When I

a <- c(1,1,1,0,0,0) b <- c(1,1,0,1,1,0) df <- data.frame(cbind(a,b))

gfci.discrete(df)

I get the following:

Graph Parameters:
structurePrior =  1 
samplePrior =  1 
maxDegree =  3 
maxPathLength =  -1 
significance =  0.05 
completeRuleSetUsed =  FALSE 
faithfulnessAssumed =  TRUE 
verbose =  FALSE 
Error in .jcall(gfci_instance, "Ledu/cmu/tetrad/graph/Graph;", "search") : 
  java.lang.NullPointerException