Solr refuses to index some documents

[emilis]

Example exceptions from Solr console:

18:25:41 [qtp1224680467-41 - /solr/update] INFO  org.apache.solr.update.processor.UpdateRequestProcessor - {add=[/docs/2010/10/08/16593]} 0 30
18:25:41 [qtp1224680467-141 - /solr/update] ERROR org.apache.solr.handler.XmlUpdateRequestHandler - Error processing "legacy" update command:javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1549,11]
Message: The entity name must immediately follow the '&' in the entity reference.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:593)
    at org.apache.solr.handler.XMLLoader.readDoc(XMLLoader.java:273)
    at org.apache.solr.handler.XMLLoader.processUpdate(XMLLoader.java:138)
    at org.apache.solr.handler.XmlUpdateRequestHandler.doLegacyUpdate(XmlUpdateRequestHandler.java:130)
    at org.apache.solr.servlet.SolrUpdateServlet.doPost(SolrUpdateServlet.java:79)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:527)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:423)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:493)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:930)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:358)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:866)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:245)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)
    at org.eclipse.jetty.server.Server.handle(Server.java:347)
    at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:594)
    at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:1059)
    at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:764)
    at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:217)
    at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:424)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:506)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436)
    at java.lang.Thread.run(Thread.java:619)

18:25:41 [qtp1224680467-29 - /solr/update] INFO  org.apache.solr.update.processor.UpdateRequestProcessor - {add=[/docs/2010/10/08/16593]} 0 7
18:25:41 [qtp1224680467-136 - /solr/update] INFO  org.apache.solr.update.processor.UpdateRequestProcessor - {add=[/docs/2010/10/08/16593]} 0 8
18:25:41 [qtp1224680467-60 - /solr/update] ERROR org.apache.solr.handler.XmlUpdateRequestHandler - Error processing "legacy" update command:javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1549,11]
Message: The entity name must immediately follow the '&' in the entity reference.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:593)
    at org.apache.solr.handler.XMLLoader.readDoc(XMLLoader.java:273)
    at org.apache.solr.handler.XMLLoader.processUpdate(XMLLoader.java:138)
    at org.apache.solr.handler.XmlUpdateRequestHandler.doLegacyUpdate(XmlUpdateRequestHandler.java:130)
    at org.apache.solr.servlet.SolrUpdateServlet.doPost(SolrUpdateServlet.java:79)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:527)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:423)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:493)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:930)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:358)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:866)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:245)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)
    at org.eclipse.jetty.server.Server.handle(Server.java:347)
    at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:594)
    at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:1059)
    at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:764)
    at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:217)
    at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:424)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:506)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436)
    at java.lang.Thread.run(Thread.java:619)