Confirm the correct instruction indeed is C:\program files\webteh\bsplayer\bsplayer.exe "%L" -ADD
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(Dutch WinXP SP3)
(P.S.: Please note that the instruction for play is C:\Program Files\Webteh\BSPlayer\bsplayer.exe "%L" and not C:\Program Files\Webteh\BSPlayer\bsplayer.exe "%1")