Hi, Hubert Hung-Hsien Chang <hubert / cs.nyu.edu> writes: :So I wrote a little .bat files :TCL_LIBRARY=c:\ruby\tcl\lib\tcl8.3; :RUBY_TCL_DLL=c:\ruby\tcl\bin\tcl83.dll; :RUBY_TK_DLL=c:\ruby\tcl\bin\tk83.dll; :PATH = %PATH;c:\ruby\bin :PATHEXT = %PATHEXT;.rb;.rbw; Remove ';'. RUBY_TCL_DLL=c:\ruby\tcl\bin\tcl83.dll RUBY_TK_DLL=c:\ruby\tcl\bin\tk83.dll Anyway, you may set up only these environment variables. PATH = %PATH;c:\ruby\bin;c:\ruby\tcl\bin PATHEXT = %PATHEXT;.rb;.rbw; -- eban