Thread:Extension talk:SolrStore/Unexpected XML tag doc/p

During a runJob exercise another error occurred, the backtrace does not say which document caused the error nor which XML tag, anyway please find the backtrace below.

The request sent by the client was syntactically incorrect (unexpected XML tag doc/p). Backtrace:
 * 0 D:\xampp\htdocs\...\extensions\SolrStore\SolrTalker.php(209): SolrTalker->solrSend('http://192.168....', ' solrAdd(' addDoc(Object(SolrDoc))
 * 3 D:\xampp\htdocs\...\extensions\SolrStore\SolrConnectorStore.php(139): SolrTalker->parseSemanticData(Object(SMWSemanticData))