problems with Sweave and the function latex(HMISC)

latex(s6a2,title="",caption="Baseline vs 
zonr",file="",label="Base",long=TRUE,landscape=F, middle.bold=TRUE,here=T,
+ 
,size="smaller[5]",outer.size="smaller",Nsize="smaller",midsize="smaller")
"latex" is not reconized \as a internalor external command ,
 un programma eseguibile o un file batch.
Warning message:
In shell(cmd, wait = TRUE, intern = output) :
  'cd "C:\DOCUME~1\giovanni\IMPOST~1\Temp\RtmpgUEV1B" & latex 
-interaction=scrollmode 
"C:\DOCUME~1\giovanni\IMPOST~1\Temp\RtmpgUEV1B\file6df11649"' execution 
failed with error code 1
TIA
GIOVanni

str(s6a2)
List of 14
 $ stats      :List of 1
Sys.info()
                     sysname                      
release                      version
                   "Windows"                         "XP" "build 2600, 
Service Pack 3"
                    nodename                      
machine                        login
                      "PC43"                        
"x86"                   "giovanni"
                        user
                  "giovanni"
[1] ".GlobalEnv"        ".GlobalTemp"       "package:Hmisc"     
"package:tools"   
 [5] "package:stats"     "package:graphics"  "package:grDevices" 
"package:utils"   
 [9] "package:datasets"  "package:methods"   "Autoloads"         
"package:base"    
R version 2.7.2

dr. Giovanni Parrinello
Department of Biotecnologies
Medical Statistics Unit
University of Brescia
Viale Europa, 11 25123 Brescia
email: parrinel at med.unibs.it
Phone: +390303717528
Fax: +390303717488