Errore in sprintf(fmt, ...) ?

hi,
i'm trying to perform a clustering on a dem (50x50 km
res=20m)
 is this is the code:


require(spgrass6)

require(cluster)

gmeta6 <- gmeta6()

x <-
readFLOAT6sp(c("er","crosc","longc","slope","profc","minic","maxic"))

morph <- data.frame(cbind(x$er, x$crosc, x$longc,
x$slope, x$profc, x$minic, x$maxic))

morph <- data.frame(cbind(x$er, x$crosc, x$longc,
x$slope/max(x$slope), x$profc, x$minic, x$maxic))

names(morph) <-
c("er","crosc","longc","slope_n","profc","minic","maxic")

print("perform the clustering")

morph.clara <- clara(morph, k=5, stand=F)

x$morph_class <- morph.clara$clustering

print("send result back to GRASS")

rast.put6(x,"morph", zcol="morph_class")
....
......
but during:
"perform the clustering"

i'had this error:

Errore in sprintf(fmt, ...) : La lunghezza della
stringa eccede la dimensione del buffer di 8192
Inoltre: Warning messages:
1: perl = TRUE ?? implementato solo nei locale UTF-8
2: perl = TRUE ?? implementato solo nei locale UTF-8
3: perl = TRUE ?? implementato solo nei locale UTF-8
4: perl = TRUE ?? implementato solo nei locale UTF-8
5: perl = TRUE ?? implementato solo nei locale UTF-8
6: perl = TRUE ?? implementato solo nei locale UTF-8
7: perl = TRUE ?? implementato solo nei locale UTF-8
8: La stringa di caratteri verr?  probabilmente
troncata
Esecuzione interrotta

if i try the same code on a subregion of my data 
(about 20x20 km res=20), it works very fine!
but for a large region i've this error :-(

obviously i think that is a memory problem, right ?
(i'm working with a notebook PPC-1.33-512ram)
my data are  : 7 raster-map on a region of about 50X40
km at a resolution of 20m.
is there some wolkaround about the memory problems?

an other question is:
what is this :
Warning messages:
1: perl = TRUE ?? implementato solo nei locale UTF-8
2: perl = TRUE ?? implementato solo nei locale UTF-8
3: perl = TRUE ?? implementato solo nei locale UTF-8
4: perl = TRUE ?? implementato solo nei locale UTF-8
5: perl = TRUE ?? implementato solo nei locale UTF-8
6: perl = TRUE ?? implementato solo nei locale UTF-8
7: perl = TRUE ?? implementato solo nei locale UTF-8

is it about this line of the code :

morph.clara <- clara(morph, k=5, stand=F)
i have an F > false


frustated for this error, to day i buy a 1 GB memory
slot for my laptop
now it have 1,28GB instead the old 512, but i've the
same error :-(
damn!damn!....how can i do?
repeat for a little area (about 20X20 km and res=20m)
it work fine!
have you any suggestion?
is ther a method for look if this error depend from my
ram or other....?
thanks foe any suggestion!
i need your help.
thanks.
Massimo