It is possible that your problem is solved by changing fileEncoding into encoding, these parameters work differently in the read function (see ?read).
oem.csv <- read.table("~/csv1.csv", sep=";", dec=",", quote="",encoding="cp866")
Just in case however, a more complete answer, as there may be some non-obvious obstacles. In short: It is possible to work with Cyrillic in R on Windows (in my case Win 7).
You may need to try a few possible encodings to get things to work. For text mining, an important aspect is to get the your input variables to match the data. There the function of Encoding() is very useful, see also iconv(). Thus it is possible to see your native parameter.
Encoding(variant <- "Минемум")
In my case the encoding is UTF-8, although this may depend on system settings. So, we can try the result with UTF-8 and UTF-8-BOM, and make a test file in notepad++ with a line of Latin and a line of Cyrillic.
UTF8_nobom_cyrillic.csv & UTF8_bom_cyrillic.csv
part2, part3, part4
Минемум конкыптам, тхэопхражтуз, ед про
This can be imported into R by
raw_table1 <- read.csv("UTF8_nobom_cyrillic.csv", header = FALSE, sep = ",", quote = """, dec = ".", fill = TRUE, comment.char = "", encoding = "UTF-8")
raw_table2 <- read.csv("UTF8_bom_cyrillic.csv", header = FALSE, sep = ",", quote = """, dec = ".", fill = TRUE, comment.char = "", encoding = "UTF-8-BOM")
The results of these are for me for BOM regular Cyrillic in the view(raw_table1), and gibberish in console.
part2, part3, part4
??????μ????? ???????????????°?? ???…?¨?????…?€?°??????
More importantly however, the script does not give access to it.
> grep("Минемум", as.character(raw_table2[2,1]))
integer(0)
The results for No BOM UTF-8, are something like this for both view(raw_table1) and console.
part2, part3, part4
<U+041C><U+0438><U+043D><U+0435><U+043C><U+0443><U+043C> <U+043A><U+043E><U+043D><U+043A><U+044B><U+043F><U+0442><U+0430><U+043C> <U+0442><U+0445><U+044D><U+043E><U+043F><U+0445><U+0440><U+0430><U+0436><U+0442><U+0443><U+0437> <U+0435><U+0434> <U+043F><U+0440><U+043E>
However, importantly, a search for the word inside will yield the correct result.
> grep("Минемум", as.character(raw_table1[2,1]))
1
Thus, it is possible to work with non-standard characters in Windows, depending on your precise goals though.
I work with non-English Latin characters regularly and the UTF-8 allows working in Windows 7 with no issues. "WINDOWS-1252" has been useful for exporting into Microsoft readers such as Excel.
PS The Russian words were generated here http://generator.lorem-ipsum.info/_russian, so essentially meaningless.
PPS The warnings you mentioned remain still with no apparent important effects.