[R] lattice smooth problem?

[Troels Ring]

Dear friends - I'm on windows, R 2.7.0
I try again asking if anyone can explain why a single pig of 16 makes so 
wild swings.
Warnings are issued, and they are
1: pseudoinverse used at 482.1
2: neighborhood radius 242.1
3: reciprocal condition number  0
4: at  360
5: radius  14400
6: all data on boundary of neighborhood. make span bigger
7: There are other near singularities as well. 14400
8: pseudoinverse used at 482.1
9: neighborhood radius 242.1
10: reciprocal condition number  0
11: at  360
12: radius  14400
13: all data on boundary of neighborhood. make span bigger
14: There are other near singularities as well. 14400

Here is the data and code, ready for copying directly to R
Best wishes
Troels

Na<-c(135,133,131,129,127,126,124,123)
ID<-c(13,13,13,13,13,13,13,13)
fit<-c(134.7945,132.9084,131.0848,129.3372,127.5546,125.8162,
124.1836,122.6077)
time<-c(60,120,180,240,300,360,420,480)
hh<-data.frame(ID=as.factor(ID),Na=Na,fit=fit,time=time)
library(lattice)
xyplot(Na+fit~time|ID,hh,type=c("g","p","smooth"),
auto.key=list(lines=TRUE))

-- 

Troels Ring - -
Department of nephrology - - 
Aalborg Hospital 9100 Aalborg, Denmark - -
+45 99326629 - -
tring at gvdnet.dk