diff --git a/ChangeLog b/ChangeLog
index beb632a551..7665d7b4a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Sep  2 18:34:57 2008  Tanaka Akira  <akr@fsij.org>
+
+	* enc/trans/make_transdb.rb: error message improved.
+
 Tue Sep  2 14:05:50 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* enc/trans/utf_16_32.trans (from_UTF_8): rename from to_UTF_16BE
diff --git a/enc/trans/make_transdb.rb b/enc/trans/make_transdb.rb
index 50d4f169f3..7dbe6db4a7 100644
--- a/enc/trans/make_transdb.rb
+++ b/enc/trans/make_transdb.rb
@@ -19,16 +19,17 @@ transdirs.each do |transdir|
   }.each do |fn|
     next if files[fn]
     files[fn] = true
-    open(File.join(transdir,fn)) do |f|
+    path = File.join(transdir,fn)
+    open(path) do |f|
       f.each_line do |line|
         if (/^static const rb_transcoder/ =~ line)..(/"(.*?)"\s*,\s*"(.*?)"/ =~ line)
           if $1 && $2
             from_to = "%s to %s" % [$1, $2]
             if converters[from_to]
-              raise ArgumentError, '%s:%d: transcode "%s" is already registered (%s:%d)' %
-              [fn, $., from_to, *converters[from_to].values_at(2, 3)]
+              raise ArgumentError, '%s:%d: transcode "%s" is already registered at %s:%d' %
+              [path, $., from_to, *converters[from_to].values_at(2, 3)]
             else
-              converters[from_to] = [$1, $2, fn[0..-3], $.]
+              converters[from_to] = [$1, $2, path, $.]
             end
           end
         end