R help - Jul 2005 - R crashes when spherical autocorrelation specified in nlme

Dear list:
R crashes when I specify spatial autocorrelation in
nlme:

sp3 <- corSpher(c(30,0.75),~x+y|Site, nugget = T)
cs3 <- Initialize(sp3, data = sav)
sav.nlme1<-nlme(vc.asin ~ SSasymp(canopy, Asym, R0,
lrc),data = sav, fixed = Asym + R0 + lrc ~ 1, random R0 + lrc ~ 1|Site, start =
list(fixed = sav.ini),
verbose = T, correlation = cs3)

There is a longish (~3 s) pause prior to the crash.
There is no crash if "correlation = cs3" is omitted.
The nugget effect is large (~0.75), so perhaps it is
not worth including, but I would still like to know if
the crash can be avoided.

My system is:
R 2.0.1
Windows XP SP2
Dual Intel Xeon 2.8GHz
2Gb RAM

Thanks,
Dan Bebber

Department of Plant Sciences
University of Oxford
UK