If you want to use Ruby/Tk (tk.rb and so on), you must have tcltklib.so 
which is working correctly. If you fail to call 'require "tcltklib"', 
you may not have tcltklib.so. When you have some troubles on compiling
tcltklib, please read README files on tcltklib. 
Even if there is a tcltklib.so on your Ruby library directry, it will not 
work without Tcl/Tk libraries (e.g. libtcl8.4.so) on your environment. 
You must also check that your Tcl/Tk is installed properly. 

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 ( the following is written in EUC-JP )

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¤¤¤Ê¤±¤ì¤Ð¤Ê¤ê¤Þ¤»¤ó¡¥¤â¤· 'require "tcltklib"' ¤Ë¼ºÇÔ¤¹¤ë¤è¤¦¤Ê¤é¡¤
tcltklib.so ¤¬¥¤¥ó¥¹¥È¡¼¥ë¤µ¤ì¤Æ¤¤¤Ê¤¤¤Î¤«¤â¤·¤ì¤Þ¤»¤ó¡¥tcltklib ¤Î
¥³¥ó¥Ñ¥¤¥ë»þ¤Ë²¿¤«ÌäÂ꤬À¸¤¸¤Æ¤¤¤ë¾ì¹ç¤Ï¡¤tcltklib ¤Î README ¥Õ¥¡¥¤¥ë
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¤¿¤È¤¨ Ruby ¤Î¥é¥¤¥Ö¥é¥ê¥Ç¥£¥ì¥¯¥È¥ê¤Ë tcltklib.so ¤¬Â¸ºß¤·¤Æ¤¤¤¿¤È¤·¤Æ
¤â¡¤¼Â¹Ô´Ä¶­¤Ë Tcl/Tk ¥é¥¤¥Ö¥é¥ê (libtcl8.4.so ¤Ê¤É) ¤¬¤Ê¤±¤ì¤Ðµ¡Ç½¤·¤Þ
¤»¤ó¡¥Tcl/Tk ¤¬Àµ¤·¤¯¥¤¥ó¥¹¥È¡¼¥ë¤µ¤ì¤Æ¤¤¤ë¤«¤â¥Á¥§¥Ã¥¯¤·¤Æ¤¯¤À¤µ¤¤¡¥

==========================================================
                Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)