A question about dbWriteTable command in R under MS Windows

Dear Sir/Madam,

I wrote the following R code (see below) to store the data frame of  
"test.01" into the table of "ttest01" in my database which is  
located on a Linux machine. If the code was run under MS Windows XP,  
I have found that the values in the last column (i.e. column f5) in  
the table are all zeros instead of NULLs. If the same R code was run  
under Linux, however, everything is OK. The R version is 2.6.0 under  
both MS Windows XP and Linux.

Does anyone know how to solve this problem under MS Windows XP?

Thank you very much for the help and time in advance. Howard

********************************************************************************************
library(DBI)
library(RMySQL)
mysqldrv <- dbDriver("MySQL")
conn.2.database<-  
dbConnect('myHostName','myUserName','myPassword','myDatabaseName')
test. 
01 
= 
data 
.frame 
(f1 
= 
c 
("A 
","B","C"),f2=c(1,2,3),f3=c(NA,NA,NA),f4=c(NA,NA,NA),f5=c(NA,NA,NA))
dbWriteTable(conn.2.database, "ttest01", test.01, row.names=F,  
eol='\r\n')
dbDisconnect(conn.2.database)

Dear Sir/Madam,

 I wrote the following R code (see below) to store the data frame of 
"test.01" into the table of "ttest01" in my database which is located on 
a Linux machine. If the code was run under MS Windows XP, I have found 
that the values in the last column (i.e. column f5) in the table are all 
zeros instead of NULLs. If the same R code was run under Linux, however, 
everything is OK. The R version is 2.6.0 under both MS Windows XP and 
Linux.

 Does anyone know how to solve this problem under MS Windows XP?

 Thank you very much for the help and time in advance. Howard

******************************************************************************************** 

library(DBI)
library(RMySQL)
mysqldrv <- dbDriver("MySQL")
conn.2.database<- 
dbConnect('myHostName','myUserName','myPassword','myDatabaseName')
test.01=data.frame(f1=c("A","B","C"),f2=c(1,2,3),f3=c(NA,NA,NA),f4=c(NA,NA,NA),f5=c(NA,NA,NA)) 

dbWriteTable(conn.2.database, "ttest01", test.01, row.names=F, eol='\r\n')
dbDisconnect(conn.2.database)