-set_up_language(getPref($data_dir, $username, 'language'));
-
-echo "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Frameset//EN\">\n".
- "<html><head>\n" .
- "<title>$org_title</title>\n".
- "</head>";
+$err=set_up_language(getPref($data_dir, $username, 'language'));
+
+$output = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Frameset//EN\">\n".
+ "<html><head>\n" .
+ "<meta name=\"robots\" content=\"noindex,nofollow\">\n" .
+ "<title>$org_title</title>\n".
+ "</head>";
+
+// Japanese translation used without mbstring support
+if ($err==2) {
+ echo $output.
+ "<body>\n".
+ "<p>You need to have php4 installed with the multibyte string function \n".
+ "enabled (using configure option --enable-mbstring).</p>\n".
+ "<p>System assumed that you accidently switched to Japanese translation \n".
+ "and reverted your language preference to English.</p>\n".
+ "<p>Please refresh this page in order to use webmail.</p>\n".
+ "</body></html>";
+ return;
+}