Share your experience!
In the menu , there is an icon with name "Video"
I assume this is a video player.
I transfered from my PC some .3gp videos to my phone.
Although I can see and play them from "Album" icon, when I go to "Video" icon it states : "No Videos"
Any ideas ?
First thing I would ask is where did you save them? Did you put them within the Video file on the SD card or just in the main part of the SD card.
I put them in --> DCIM>100MSDCF folder
There is no such folder as "Video"
Other folders are , "Android" , "Thumbnails" etc etc.
Are you now using a file manager? If you are in the DCIM (/sdcard/DCIM) file then you need to go back up a level to the root of the SD card and then scroll through til you find the Video file. The various programmes are preset to look in certain files so I am thinking that the Video icon on the application drawer only looks in the Video file on the SD card.
You was absolutely right 
Videos copied to the root of the SD card are viewable from the "Video" application.
So this means that I cant create folders to organize my videos.
In contrast , all the mp3 files I copied to a newly created folder inside DCIM directory
are playable by the "Music Player".
Weird behavior
As long as you have it working... don't question the weirdness!! Seriously tho glad you can get it organised your way now.
If there is anything else... you know where to shout!
Enjoy your phone.
BTW mp3's can be stored in the 'Music' file if you feel like living dangerously 
What do you mean by that ???
Sorry all I meant is that you can put them in the Music folder on the SD card which in an ideal world would be the 'right' place for them, but hey if its working your way no reason to change it! My only proviso would be that if you downloaded a third party app for media, such as Zimly or Mixzing then they may not 'think' to look anywhere else for music if not in the music file and videos if not in the video file.
I think I have just created a thread on a similar issue.
http://talk.sonyericsson.com/thread/26547
Bearing in mind I am UBER stupid at understanding techy stuff, is it r would it be possible for you to explain this:
Suze: Are you now using a file manager? If you are in the DCIM (/sdcard/DCIM) file then you need to go back up a level to the root of the SD card and then scroll through til you find the Video file. The various programmes are preset to look in certain files so I am thinking that the Video icon on the application drawer only looks in the Video file on the SD card.
...in simplistic terminology.
So grateful if I could get some help.