diff -urN ../htmllint.orig/htmllint.cgi ./htmllint.cgi
--- ../htmllint.orig/htmllint.cgi	Fri May  9 01:21:00 2014
+++ ./htmllint.cgi	Fri May  9 01:22:00 2014
@@ -213,7 +213,7 @@
   &ErrorExit($LOGSDIR.$msgCannotMkdir);
  }
 } else {
- $SCOREFILE = $SCORECOUNTER = $STATFILE = '';
+ $SCOREFILE = $SCORECOUNTER = $STATFILE = $ERRORFILE = '';
 }
 
 # HTMLをローカルに得る
@@ -997,6 +997,7 @@
 sub ErrorExit
 {
  my (@msgs) = @_;
+ &LogError(@msgs) if $ERRORFILE;
  &PrintHTMLHeader("$PROGNAME error!");
  &Jprint(qq|<h2>$PROGNAME error!</h2>\n|);
  while (@msgs) {
@@ -1082,6 +1083,38 @@
 EndOfHTMLFooter
 }
 
+# エラーの記録
+sub LogError
+{
+ my $errmsg = join('', @_);
+ $errmsg =~ s/<br.*?>/ /oig;
+ $errmsg =~ s/<\/?.*?>//oig;
+ $errmsg =~ s/&amp;/&/oig;
+ $errmsg =~ s/&lt;/</oig;
+ $errmsg =~ s/&gt;/>/oig;
+#$errmsg =~ s/&quot;/"/oig;
+
+ my $request = $ENV{'REQUEST_METHOD'};
+ my $method = $cgi->param('Method');
+ $method =~ s/(\W)/'%'.unpack('H2',$1)/oge; # 念のため
+ $method ||= '-';
+
+ my $file = $ERRORFILE;
+ my ($sec, $min, $hour, $mday, $mon, $year) = localtime(time);
+ my $post = sprintf('%04d%02d', 1900+$year, 1+$mon);
+ $file =~ s/#/$post/g;
+ my $existfile = -e $file;
+ if (open(LOGF, ($existfile? '>>': '>').$file)) {
+  flock(LOGF, 2) if $UNIX;
+  my $rhost = ($ENV{REMOTE_HOST} or $ENV{REMOTE_ADDR});
+  print LOGF sprintf('%04d/%02d/%02d %02d:%02d:%02d', 1900+$year, 1+$mon, $mday, $hour, $min, $sec),
+                     " $rhost $request $method \"$errmsg\"\n";
+# flock(LOGF, 8) if $UNIX;
+  close(LOGF);
+  chmod 0766, $file;
+ }
+}
+
 # 得点の記録
 sub LogScore
 {
diff -urN ../htmllint.orig/htmllintenv ./htmllintenv
--- ../htmllint.orig/htmllintenv	Sun May  4 00:30:00 2014
+++ ./htmllintenv	Sun May  4 01:49:41 2014
@@ -98,6 +98,10 @@
 #$SCOREFILE    = "${LOGSDIR}score#.log";
 #$SCORECOUNTER = "${LOGSDIR}score.cnt";
 
+# エラー記録用ログファイル (不要ならコメントアウト)
+#   # の部分は年月に置き換わります
+$ERRORFILE    = "${LOGSDIR}error#.log";
+
 # 警告の統計用ログファイル (不要ならコメントアウト)
 #   # の部分は年月に置き換わります
 #$STATFILE = "${LOGSDIR}statistics#.log";