Error in partysplit(varid = which(rownames(obj$split)[j] == names(mf)),  :
‘index’ has less than two elements

node), split, n, deviance, yval
  * denotes terminal node

 1) root 354 244402.100 75.45134
2) hr.11a14>=49.2125 19   3378.322 33.44274 *
3) hr.11a14< 49.2125 335 205592.400 77.83391
 6) month=April,February,June,March,May 141  58656.390 68.57493 *
 7) month=August,December,January,July,November,October,September 194 126062.800 84.56338
  14) presion.11a14>=800.925 91  74199.080 81.32755
    28) month=January,November,October 16   9747.934 63.13394 *
    29) month=August,December,July,September 75  58025.190 85.20885 *
  15) presion.11a14< 800.925 103  50069.100 87.42223 *