diff --git a/ChangeLog b/ChangeLog
index faf07f16..c2e0713e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-04-03  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
+
+	Changed error message.
+	* src/XmlRpcMethod.cc
+
 2010-04-03  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
 
 	Added bt-tracker-timeout, bt-tracker-connect-timeout,
diff --git a/src/XmlRpcMethod.cc b/src/XmlRpcMethod.cc
index 0a6e7f0c..536df400 100644
--- a/src/XmlRpcMethod.cc
+++ b/src/XmlRpcMethod.cc
@@ -80,16 +80,17 @@ XmlRpcResponse XmlRpcMethod::execute
 template<typename InputIterator>
 static void gatherOption
 (InputIterator first, InputIterator last,
- const std::set<std::string>& changeableOptions,
+ const std::set<std::string>& allowedOptions,
  const SharedHandle<Option>& option,
  const SharedHandle<OptionParser>& optionParser)
 {
   for(; first != last; ++first) {
     const std::string& optionName = (*first).first;
-    if(changeableOptions.count(optionName) == 0) {
+    if(allowedOptions.count(optionName) == 0) {
       throw DL_ABORT_EX
         (StringFormat
-         ("%s cannot be changed or unknown option.", optionName.c_str()).str());
+         ("%s option cannot be used in this context.",
+          optionName.c_str()).str());
     } else {
       SharedHandle<OptionHandler> optionHandler =
         optionParser->findByName(optionName);