im-switcher opens a private file.
http://freedesktop.org/pipermail/uim/2004-October/000702.html

$ strace -f -F -o ~/uim-strace.txt uim-toolbar-gtk
Click 'sw'
You'll find "No such file or directory" in terminal.
=> Quit uim-toolbar-gtk

$ gedit uim-strace.txt
Search "no such file" from backward.
You'll find these lines:
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!! 4916  open("/home/tkng/uim.d/im-switcher", O_RDONLY <unfinished ...>
4914  <... ioctl resumed> , [0])        = 0
4916  <... open resumed> )              = -1 ENOENT (No such file or directory)
4914  poll( <unfinished ...>
4916  write(2, "No such file or directory\n", 26) = 26
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