I saw you have W850i, that has 320*240 screen resolution. Now, you should get download acces soon, the download flash menu for your screen size, if there aren't thm files for every swf, you can edit any existing thm file (for your screen resolution of course) to work with any swf file.
I'll try to explain how to associate a thm to a swf:
-open Total Commander
-go to the thm you want to asociate to the swf
-rename from ****.thm to ****.tar
-enter
-look for Theme.xml press F4 you'll be asked if you want to unpack and edit, press yes
-a notepad will open
-first lines should look something like this:
<?xml version="1.0"?>
<!-- Created with Sony Ericsson Themes Creator -->
<Sony_Ericsson_theme version="4.5">
-after this line: <Sony_Ericsson_theme version="4.*"> write this
<Desktop_style Type="File" Source="name_of_file.swf" />
-Save
-Close Notepad
-you'll be asked if you want to repack it into the .tar file (previous .thm), press Yes
-exit tar archive
-rename from ****.tar to ****.thm
that's it, this works for 174*220px flash menus and themes, i think this should work to 320*240px menus and themes too.
Good luck!