Напрямую срабатывает:
Код:
^Q "i21sysCalls.Start('winebrowser http://ya.ru/')"
Если подходить к i21sysCalls.Open прежде всего как к команде открытия ссылок на веб-страницы, можно использовать такой "кроссплатформенный" 
хак:Код:
MODULE i21sysCalls; (** **)
...
PROCEDURE ( a: Action ) Do;
...
hinst := WinApi.ShellExecute( hwnd, lpOperation, lpFile, lpParameters, lpDirectory, nShowCmd );
IF (hinst # 0)
& (win_fileName[0] = "h")
& (win_fileName[1] = "t")
& (win_fileName[2] = "t")
& (win_fileName[3] = "p")
& (win_fileName[4] = ":")
& (win_fileName[5] = "/")
& (win_fileName[6] = "/")
THEN
Start("winebrowser " + win_fileName)
END
...
END Do;
...
PROCEDURE ( a: Action ) Do;
...
hinst := WinApi.ShellExecute( hwnd, lpOperation, lpFile, lpParameters, lpDirectory, nShowCmd );
IF (hinst # 0)
& (win_fileName[0] = "h")
& (win_fileName[1] = "t")
& (win_fileName[2] = "t")
& (win_fileName[3] = "p")
& (win_fileName[4] = ":")
& (win_fileName[5] = "/")
& (win_fileName[6] = "/")
THEN
Start("winebrowser " + win_fileName)
END
...
END Do;