xml解析问题！急

我是利用axiom对xml进行解析！
但却出现下面的错误！
Exception in thread "main" org.apache.axiom.om.OMException: [com.ctc.wstx.exc.WstxLazyException] com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character ' ' (code 32) (missing name?)
at [row,col {unknown-source}]: [136,53]
程序在执行有些xml文件时没有问题，有些却有问题。我很苦恼！是不是我的xml文件有问题啊？
Java code:

public class AxiomDemo {

public static void writeToFile(OutputStream os, byte[] b) {//写内容写到文件里面

try {
os.write(b, 0, b.length);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public static void writeToFile(OutputStream os, OMElement om) {
try {
String str = om.toStringWithConsume();
byte[] b = str.getBytes();
//os.write(b, 0, b.length);
writeToFile(os, b);
} catch (XMLStreamException e) {
// TODO: handle exception
}
}

public static OMElement readQuestionXml(InputStream is) {
OMElement om = null;
try {
XMLStreamReader parser = XMLInputFactory.newInstance()
.createXMLStreamReader(is);
StAXOMBuilder builder = new StAXOMBuilder(parser);