here are all the required DW-steps. In order you could control this, I'll try to describe in detail from the beginning (translated from my German DW):
Create a really new subdirectory (only for this trial, later put in your file in question).
Create a new html/php-file(only for this trial).
Work in designMode --> Insert Flash-Video.
Search/browse ---> yourFLV.flv
Skin: Halo Skin 3 (min. width 280) ( it was my choice)
width 640 ( it's my choice)
height 480 ( it's my choice)
I clicked all the boxes
---> And now away with all these files below (produced from DW) to your server and there in your directory you have worked with.
Best you have a look with WIN-Explorer into your directory, to see all the files DW has created in your subdirectory and don't forget one):
YourFlv.htm (or YourFlv.php)
Clear_Skin_1.swf (my choice)