It is highly advised to not export anything compressed from your editing program. You want to export a lossless AVI to a codec like
Ut Video. Get the latest version and install both x86 and x64 if you are using 64-bit Windows. Then select the YUV420 (ULY0) option for your AVI video codec. Then encode to a MP4/MKV using something like
Zarx264gui.
Looking at your current video you uploaded it is in VP6 (horrible codec for efficiency and quality, H.264/x264 is preferred), 780x576 resolution (it should be 640x480 to save space and correct aspect ratio) 30 fps (should be 29.970 or 23.976, depending on source), and the audio is 32.0 Kbps at 11 Khz (terrible audio quality, should be at least 160 Kbps at 44.1 Khz).
MediaInfo of the file for people that are curious:
As far as no preview, I'm guessing whatever the "org" is using to decode and encode files doesn't like your file. Maybe someone involved with that part could shed some more light on it.
Insert clever text/image here.