Hi. Another new guy in the forum!!!

I just acquired the Philips 42pfl4007. Great image and sound quality. Easy to use.
However, I am having difficulties with the Smart functionalities. I have purchased the Smart TV to reproduce multimedia located in my PC (videos mainly). But I found some issues described below:

1) File size: files greater then 1.4Mb do not play. --> for this issue I didn't find any solution in the forum.
2) Subtitles: movie subtitles do not appear even when I turned them on. --> I understand reading other topics that the Windows Media server might be the responsible.
3) File format: .mkv files do not play. --> I have replaced the Windows Media server with PS3 and Wild Media Server. While I can now play the .mkv files (transcoded to .mpg) and read the subtitles with WMS, the movies stop constantly. I have a wireless connection of 6Mb. --> Any idea why? Might be a WMS configuration matter?

I really like to address these issues in order to take advantage of the Smart TV features.
Can somebody help me?
Thanks in advance.