R help - Feb 2003 - rpart- error rate for survival regression?

Hello

I am using rpart with survival data.  When I 'printcp'
I get the results below.  Can someone please explain
two things for me in lay man's terms.  1) What exactly
is the complexity parameter?  2) How do I calculate
the absolute cross validated error rate when the root
node error in my example is 1.39?

Thanks you.

spok leen


Survival regression tree:
rpart(formula = Surv(fu, death) ~ p + k + c + 
    g + a + e, data = dat2, xval = 700)

Variables actually used in tree construction:
[1] c e  k  p a 

Root node error: 972.86/700 = 1.3898

n= 700 

        CP nsplit rel error  xerror     xstd
1 0.068408      0   1.00000 1.00390 0.048144
2 0.036091      1   0.93159 0.93917 0.048700
3 0.025606      2   0.89550 0.94267 0.052853
4 0.022596      3   0.86990 0.90079 0.052251
5 0.011670      4   0.84730 0.87244 0.050768
6 0.010000      5   0.83563 0.90675 0.053937