failing to require "lfs"

[christof@...]

Hello,

I downloaded the last win32-binaries for
  Lua5.1.3
  lua filesystem

I set the paths LUA_DUR and LUA_CPATH as required and
copied lfs.dll to the LUA_CPATH-location.

But when I do  require"lfs" ,I get this:

lua5: test-lfs-neu.lua:8: module 'lfs' not found:
        no field package.preload['lfs']
        no file 'lfs.lua'
        no file '%LUA_DIR%\lfs.lua'
        no file 'lfs.dll'
        no file '%LUA_DIR%\lfs.dll'
stack traceback:
        [C]: in function 'require'
        test-lfs-neu.lua:8: in main chunk
        [C]: ?

It has been asked before, but I execpt 'build it yourself'
I couldn't find an answer. Shouldn't binaries be working
out of the box? Who can help?

Thanks
Christof