Can't Open world

Is there any way to open this file after getting this error....

Unable to load world: /Users/student/Desktop/Bob's Lunar Adventure.a2w


Alice version: 2.0.7
os.name: Mac OS X
os.version: 10.4.11
os.arch: ppc
java.vm.name: Java HotSpot(TM) Client VM
java.vm.version: 1.4.2-86
user.dir: /Applications/Alice.app/Contents/Required

Throwable that caused the error:
java.lang.InternalError: jzentry == 0,
jzfile = 3306800,
total = 422,
name = /Users/student/Desktop/Bob's Lunar Adventure.a2w,
i = 1,
message = invalid LOC header (bad signature)
at java.util.zip.ZipFile$2.nextElement(ZipFile.java:3 22)
at edu.cmu.cs.stage3.io.ZipFileTreeLoader.open(ZipFil eTreeLoader.java:72)
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l.loadWorld(AuthoringTool.java:1889)
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l.loadWorld(AuthoringTool.java:1856)
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l.showStartUpDialog(AuthoringTool.java:1325)
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l.openWorld(AuthoringTool.java:1338)
at edu.cmu.cs.stage3.alice.authoringtool.Actions$2.ac tionPerformed(Actions.java:88)
at javax.swing.AbstractButton.fireActionPerformed(Abs tractButton.java:1819)
at javax.swing.AbstractButton$ForwardActionEvents.act ionPerformed(AbstractButton.java:1872)
at javax.swing.DefaultButtonModel.fireActionPerformed (DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultB uttonModel.java:258)
at javax.swing.AbstractButton.doClick(AbstractButton. java:321)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Bas icMenuItemUI.java:1113)
at javax.swing.plaf.basic.BasicMenuItemUI$MouseInputH andler.mouseReleased(BasicMenuItemUI.java:943)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEven tMulticaster.java:231)
at java.awt.Component.processMouseEvent(Component.jav a:5166)
at java.awt.Component.processEvent(Component.java:496 3)
at java.awt.Container.processEvent(Container.java:161 3)
at java.awt.Component.dispatchEventImpl(Component.jav a:3681)
at java.awt.Container.dispatchEventImpl(Container.jav a:1671)
at java.awt.Component.dispatchEvent(Component.java:35 43)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:3527)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:3242)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:3172)
at java.awt.Container.dispatchEventImpl(Container.jav a:1657)
at java.awt.Window.dispatchEventImpl(Window.java:1606 )
at java.awt.Component.dispatchEvent(Component.java:35 43)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 480)
at java.awt.EventDispatchThread.pumpOneEventForHierar chy(EventDispatchThread.java:234)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:178)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:170)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:100)

[x2495iiii]

I googled some of the key terms in the message, and the Java bug report site had this:

"The most likely cause of this problem is a corrupt
jar file. However, it is also possible that the
compiler runs out of memory. So if you suspect
you're running out of memory, try increasing the
system memory or compiling a smaller set of files."

Just how big is Bob's Space Adventure? If there are too many objects, this may be the problem (my personal limit to filesize of Alice worlds is 20mb, any larger than that and it's a gamble). To reduce the filesize outside of Alice, you have to unzip the .a2w file (change the extension to .zip), then delete object files inside the folder which aren't necessary to events and actions in the world. Then re-zip the file and change the extension back to .a2w and try loading it. You could also try the backups if this doesn't work.

If it's smaller than that, the problem could also be limited memory on the computer you're using. Try a different computer.

Finally, if none of these work, the world has been corrupted somehow and may be unrecoverable. If this is the case, you can always post it here and let me try fixing it.

there also can be that the file is saved on a pc not a mac and if so on a mac the file was not saved properly its corrput

[x2495iiii]

I didn't know that was an issue (but then again, I avoid Macs like the plague).

Very informative, thanks rockstar442.