When I start Jenkins, the following message appears in the error log:

Oct 10, 2012 3:14:51 PM hudson.model.Descriptor save
WARNING: Failed to save C:\Program Files\Jenkins\hudson.plugins.ircbot.IrcPublisher.xml
java.io.IOException: Unable to delete C:\Program Files\Jenkins\hudson.plugins.ircbot.IrcPublisher.xml
at hudson.util.AtomicFileWriter.commit(AtomicFileWriter.java:112)
at hudson.XmlFile.write(XmlFile.java:178)
at hudson.model.Descriptor.save(Descriptor.java:758)
at hudson.plugins.ircbot.IrcPublisher$DescriptorImpl.readResolve(IrcPublisher.java:522)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.thoughtworks.xstream.converters.reflection.SerializationMethodInvoker.callReadResolve(SerializationMethodInvoker.java:46)
at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:222)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:60)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:137)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:33)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:926)
at hudson.util.XStream2.unmarshal(XStream2.java:103)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:912)
at hudson.XmlFile.unmarshal(XmlFile.java:160)
at hudson.model.Descriptor.load(Descriptor.java:779)
at hudson.plugins.ircbot.IrcPublisher$DescriptorImpl.<init>(IrcPublisher.java:204)
at hudson.plugins.ircbot.IrcPublisher.<clinit>(IrcPublisher.java:55)
at sun.reflect.GeneratedSerializationConstructorAccessor27.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.thoughtworks.xstream.converters.reflection.Sun14ReflectionProvider.newInstance(Sun14ReflectionProvider.java:76)
at hudson.util.RobustReflectionConverter.instantiateNewInstance(RobustReflectionConverter.java:375)
at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:220)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:60)
at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.readItem(AbstractCollectionConverter.java:71)
at hudson.util.CopyOnWriteList$ConverterImpl.unmarshal(CopyOnWriteList.java:193)
at hudson.util.DescribableList$ConverterImpl.unmarshal(DescribableList.java:263)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at hudson.util.RobustReflectionConverter.unmarshalField(RobustReflectionConverter.java:332)
at hudson.util.RobustReflectionConverter.doUnmarshal(RobustReflectionConverter.java:274)
at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:221)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:60)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:137)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:33)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:926)
at hudson.util.XStream2.unmarshal(XStream2.java:103)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:912)
at com.thoughtworks.xstream.XStream.fromXML(XStream.java:864)
at hudson.XmlFile.read(XmlFile.java:137)
at hudson.model.Items.load(Items.java:220)
at jenkins.model.Jenkins$17.run(Jenkins.java:2507)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:146)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:883)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

I'm running Jenkins ver. 1.487-SNAPSHOT (private-10/10/2012 17:11 GMT-jenkins).