"Unable to Load World!" Who helps me plz :((

[ptc1760]

My presentation is coming ahead next week,
And few days ago I opened the final project that I had done one day before, and it appears that error ( I dont understand at all what happed with my project and my Alice program.
can anyone help me fix this problem plz? Thank so much!

This is the error message:

Unable to load world




Alice version: 2.2  08/05/2011



Throwable that caused the error:

java.lang.NullPointerException

	at edu.cmu.cs.stage3.alice.core.geometry.Text3D.updateExtrusion(Text3D.java:87)

	at edu.cmu.cs.stage3.alice.core.geometry.Text3D.propertyChanged(Text3D.java:77)

	at edu.cmu.cs.stage3.alice.core.Element.propertyChanged(Element.java:265)

	at edu.cmu.cs.stage3.alice.core.Property.onChanged(Property.java:423)

	at edu.cmu.cs.stage3.alice.core.Property.onSet(Property.java:438)

	at edu.cmu.cs.stage3.alice.core.Property.set(Property.java:455)

	at edu.cmu.cs.stage3.alice.core.Property.decodeObject(Property.java:626)

	at edu.cmu.cs.stage3.alice.core.Property.decode(Property.java:641)

	at edu.cmu.cs.stage3.alice.core.Element.load(Element.java:1460)

	at edu.cmu.cs.stage3.alice.core.Element.load(Element.java:1477)

	at edu.cmu.cs.stage3.alice.core.Element.load(Element.java:1477)

	at edu.cmu.cs.stage3.alice.core.Element.load(Element.java:1525)

	at edu.cmu.cs.stage3.alice.authoringtool.dialog.LoadElementProgressPane.construct(LoadElementProgressPane.java:37)

	at edu.cmu.cs.stage3.progress.ProgressPane$2.run(ProgressPane.java:84)

	at java.lang.Thread.run(Thread.java:662)