[2010-08-23 14:56:10 - TxtReader] trouble processing "java/net/DatagramPacket.class":[2010-08-23 14:56:10 - TxtReader] Attempt to include a core class (java.* or javax.*) in something otherthan a core library. It is likely that you have attempted to includein an application the core library (or a part thereof) from a desktopvirtual machine. This will most assuredly not work. At a minimum, itjeopardizes the compatibility of your app with future versions of theplatform. It is also often of questionable legality.If you really intend to build a core library -- which is onlyappropriate as part of creating a full virtual machine distribution,as opposed to compiling an application -- then use the"--core-library" option to suppress this error message.If you go ahead and use "--core-library" but are in fact building anapplication, then be forewarned that your application will still failto build or run, at some point. Please be prepared for angry customerswho find, for example, that your application ceases to function oncethey upgrade their operating system. You will be to blame for thisproblem.If you are legitimately using some code that happens to be in a corepackage, then the easiest safe alternative you have is to repackagethat code. That is, move the classes in question into your own packagenamespace. This means that they will never be in conflict with coresystem classes. If you find that you cannot do this, then that is anindication that the path you are on will ultimately lead to pain,suffering, grief, and lamentation.[2010-08-23 14:56:10 - TxtReader] 1 error; aborting[2010-08-23 14:56:10 - TxtReader] Conversion to Dalvik format failed with error 1
网上搜索到下面的解决：
android低版本工程（如1.5）放到高版本环境中（如2.2）可能会上述错误，解决方法如下：
1。 如果不修改android sdk版本，则使用project clean 命令作用于某工程即可。
（该处理方式只是在高版本中兼容了低版本工程，未真正意义上的升级）
2。 如果修改android sdk版本，则需要以下几个步骤：
1）修改SDK
选择工程，build path --> configure build path ---> library 删除引用的低版本SDK，
然后add External JARs,选择高版本SDK,OK,保存
2）修改classpath文件
该文件可能存在该项: <classpathentry kind="lib" path ="你所指定的高版本的地址"
把她修改成<classpathentry kind="con" path="com.android.ide.eclipse.adt.ANDROID_FRAMEWORK" />
3) 修改AndroidManifest.xml
在AndroidManifest.xml文件中，application标签后添加<uses-sdk android:minSdkVersion="3"></uses-sdk>
4) 修改default.properties（很重要）
该文件最后一行（前面没用#的）target=android-3 该成target=android-8，保存。
再看看你的工程和新建的android 2.2的工程结构就一样了。
其中的第二步的处理在每个工程的.classpath都需要做，最好是自己建一个android的Library，Eclipse里创建自己的library步骤：java build path-->libraries【点击Add Library】-->User Library-->User Libraries-->New-->选择新建的library点击Add JARS.
这样以后在网上下载的源码直接add自己的libraries就可以正常运行了。^_^