Xoro 415 DVD Player!

Recently I bought the new Xoro 415. The main reason I bought it was its ability to play Mpeg4 (DivX and Xvid) and so far I haven't that many problems playing my divx movies.
My main problem is subtitles. Sometimes it does play for instance .srt files and sometimes not and that's what I dont understand... it's the same sub-format. And usually I check on the computer if the subtitle is sync. with the movie, but after I burn the disc the subs dont match at all (and sometimes the audio either for that matter).
Does anyone know of a firmware update or anything else that could help me fix this problem? Thank you all!