What does this error mean?

Hi,

I think we still need at least the output of

 sessionInfo()

and the actual code you are using
Just copy the code and paste it between three ` like this

```
dat1  <- import("rows.csv")

write.xlsx(dat1, "cath1.xlsx", sheetName="Sheet1", col.names=TRUE, row.names= FALSE, append=FALSE, showNA=TRUE, password= "Casper")

dat2  <- read.xlsx("cath1.xlsx", sheetName="Sheet1", password= "Casper")

```

If you open the .csv file in a text editor does in look like there are any non-ascii characters in it. Something as simple as é or ô or perhaps a Chinese ideogram?