map converter 1.1 to 2.0 error

[rundat]

java.lang.NullPointerException

at java.io.DataInputStream.readByte(Unknown Source)

at nbt.TagInputStream.readTag(TagInputStream.java:41)

at pfaeff.IDChanger.changeIDs(IDChanger.java:574)

at pfaeff.IDChanger$1.doInBackground(IDChanger.java:483)

at javax.swing.SwingWorker$1.call(Unknown Source)

at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)

at java.util.concurrent.FutureTask.run(Unknown Source)

at javax.swing.SwingWorker.run(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)

wat do? :-\

[Puck7845]

I got this error as well! It got to 53% total progress, then stopped, generated the error log, and told me to come here, I'm going to try running it on one of the backups of the world file.

Meanwhile, anyone here that speaks java that can pinpoint what this error is about?

My error (just in case I missed something when I compared the two):

java.lang.NullPointerException

	at java.io.DataInputStream.readByte(Unknown Source)

	at nbt.TagInputStream.readTag(TagInputStream.java:41)

	at pfaeff.IDChanger.changeIDs(IDChanger.java:574)

	at pfaeff.IDChanger$1.doInBackground(IDChanger.java:483)

	at javax.swing.SwingWorker$1.call(Unknown Source)

	at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)

	at java.util.concurrent.FutureTask.run(Unknown Source)

	at javax.swing.SwingWorker.run(Unknown Source)

	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

	at java.lang.Thread.run(Unknown Source)