diff --git a/ext/tk/lib/tk.rb b/ext/tk/lib/tk.rb
index 8561a9d222..c6c0e799d7 100644
--- a/ext/tk/lib/tk.rb
+++ b/ext/tk/lib/tk.rb
@@ -191,6 +191,7 @@ module TkComm
     conf
   end
   private :hash_kv
+  module_function :hash_kv
 
   def array2tk_list(ary)
     ary.collect{|e|
@@ -205,6 +206,7 @@ module TkComm
     }.join(" ")
   end
   private :array2tk_list
+  module_function :array2tk_list
 
   def bool(val)
     case val
@@ -307,15 +309,16 @@ module TkComm
 
   def _curr_cmd_id
     #id = format("c%.4d", Tk_IDs[0])
-    id = "c" + Tk_IDs[0]
+    id = "c" + TkComm::Tk_IDs[0]
   end
   def _next_cmd_id
     id = _curr_cmd_id
     #Tk_IDs[0] += 1
-    Tk_IDs[0].succ!
+    TkComm::Tk_IDs[0].succ!
     id
   end
   private :_curr_cmd_id, :_next_cmd_id
+  module_function :_curr_cmd_id, :_next_cmd_id
 
   def install_cmd(cmd)
     return '' if cmd == ''
@@ -332,6 +335,7 @@ module TkComm
     TkCore::INTERP.tk_cmd_tbl.delete(id)
   end
   private :install_cmd, :uninstall_cmd
+  module_function :install_cmd
 
   def install_win(ppath,name=nil)
     if !name or name == ''
@@ -1213,8 +1217,8 @@ module Tk
       if bar
 	@xscrollbar = bar
 	@xscrollbar.orient 'horizontal'
-	self.xscrollcommand {|arg| @xscrollbar.set(*arg)}
-	@xscrollbar.command {|arg| self.xview(*arg)}
+	self.xscrollcommand {|*arg| @xscrollbar.set(*arg)}
+	@xscrollbar.command {|*arg| self.xview(*arg)}
       end
       @xscrollbar
     end
@@ -1222,8 +1226,8 @@ module Tk
       if bar
 	@yscrollbar = bar
 	@yscrollbar.orient 'vertical'
-	self.yscrollcommand {|arg| @yscrollbar.set(*arg)}
-	@yscrollbar.command {|arg| self.yview(*arg)}
+	self.yscrollcommand {|*arg| @yscrollbar.set(*arg)}
+	@yscrollbar.command {|*arg| self.yview(*arg)}
       end
       @yscrollbar
     end
diff --git a/ext/tk/lib/tkdialog.rb b/ext/tk/lib/tkdialog.rb
index 2c280d5618..b15b79421b 100644
--- a/ext/tk/lib/tkdialog.rb
+++ b/ext/tk/lib/tkdialog.rb
@@ -74,6 +74,7 @@ class TkDialog2 < TkWindow
       @title   = keys['title'] if keys.key? 'title'
       @message = keys['message'] if keys.key? 'message'
       @bitmap  = keys['bitmap'] if keys.key? 'bitmap'
+      @bitmap  = '{}' if @bitmap == nil || @bitmap == ""
       @default_button = keys['default'] if keys.key? 'default'
       @buttons = keys['buttons'] if keys.key? 'buttons'
 
diff --git a/ext/tk/lib/tktext.rb b/ext/tk/lib/tktext.rb
index 34663f35b4..a28c3d31fc 100644
--- a/ext/tk/lib/tktext.rb
+++ b/ext/tk/lib/tktext.rb
@@ -40,7 +40,7 @@ class TkText<TkTextWin
   end
 
   def init_instance_variable
-    @cmdtbl = {}
+    @cmdtbl = []
     @tags = {}
   end
 
diff --git a/ext/tk/sample/tkbiff.rb b/ext/tk/sample/tkbiff.rb
index ac27184437..5fe367fd97 100644
--- a/ext/tk/sample/tkbiff.rb
+++ b/ext/tk/sample/tkbiff.rb
@@ -12,7 +12,7 @@ if ARGV.length == 0
   if ENV['MAIL']
     $spool = ENV['MAIL']
   else  
-    $spool = '/usr/spool/mail/' + ENV['USER']
+    $spool = '/var/spool/mail/' + ENV['USER']
   end
 else 
   $spool = ARGV[0]
@@ -70,7 +70,13 @@ end
 
 require "tkscrollbox"
 
+my_appname = Tk.appname('tkbiff')
 $top = TkRoot.new
+if ((TkWinfo.interps($top) - [my_appname]).find{|ip| ip =~ /^tkbiff/})
+  STDERR.print("Probably other 'tkbiff's are running. Bye.\n")
+  exit
+end
+
 $top.withdraw
 $list = TkScrollbox.new($top) {
   relief 'raised'
@@ -136,12 +142,12 @@ def pop_up
     $list.see 'end'
   end
   $top.deiconify
-  Tk.after 2000, proc{$top.withdraw}
+  Tk.after 2000, proc{$top.iconify}
 end
 
 $list.insert 'end', "You have no mail."
 check
-Tk.after 2000, proc{$top.withdraw}
+Tk.after 2000, proc{$top.iconify}
 begin
   Tk.mainloop
 rescue
diff --git a/ext/tk/sample/tkdialog.rb b/ext/tk/sample/tkdialog.rb
index e83e16d0a8..73708945fb 100644
--- a/ext/tk/sample/tkdialog.rb
+++ b/ext/tk/sample/tkdialog.rb
@@ -54,7 +54,6 @@ bot.pack
 root.pack('side'=>'top', 'fill'=>'both', 'expand'=>'yes')
 
 def quit(button)
-  print "aaa\n"
   print "You pressed the \"#{button}\" button;  bye-bye!\n"
   exit
 end
diff --git a/ext/tk/sample/tkfrom.rb b/ext/tk/sample/tkfrom.rb
index 8c3efb8137..e0e7f4810f 100644
--- a/ext/tk/sample/tkfrom.rb
+++ b/ext/tk/sample/tkfrom.rb
@@ -54,9 +54,9 @@ if ARGV.length == 0
   if ENV['MAIL']
     ARGV[0] = ENV['MAIL']
   elsif ENV['USER']
-    ARGV[0] = '/usr/spool/mail/' + ENV['USER']
+    ARGV[0] = '/var/spool/mail/' + ENV['USER']
   elsif ENV['LOGNAME']
-    ARGV[0] = '/usr/spool/mail/' + ENV['LOGNAME']
+    ARGV[0] = '/var/spool/mail/' + ENV['LOGNAME']
   end
 end
 
@@ -64,7 +64,7 @@ require "tk"
 list = scroll = nil
 TkFrame.new{|f|
   list = TkListbox.new(f) {
-    yscroll proc{|idx|
+    yscroll proc{|*idx|
 	scroll.set *idx
     }
     relief 'raised'
@@ -94,7 +94,7 @@ root.bind "space", proc{exit}
 
 $outcount = 0;
 for file in ARGV
-  next if File.exist?(file)
+  next unless File.exist?(file)
   atime = File.atime(file)
   mtime = File.mtime(file)
   f = open(file, "r")