I did
| w |
w _ WebBookmarks initialize.
 (ImageSegment new copyFromRootsForExport: (Array with: w with: w class))
		writeForExport: 'myFile.extSeg'.
and got the following walkback. What do I have to do?

25 June 2002 2:35:15 pm

VM: Win32 - Squeak3.2gamma of 12 January 2002 [latest update: #4858]
Image: Squeak3.2gamma [latest update: #4889]

DummyStream(Object)>>doesNotUnderstand:
	Receiver: a DummyStream
	Arguments and temporary variables:
		aMessage: 	a Message with selector: #nextInt8Put: and arguments: #(1)
	Receiver's instance variables:
a DummyStream

ReferenceStream(DataStream)>>writeInteger8:
	Receiver: a ReferenceStream
	Arguments and temporary variables:
		anInteger: 	1
	Receiver's instance variables:
		byteStream: 	a DummyStream
		topCall: 	an ImageSegment
		basePos: 	47
		floatsAs32Bits: 	nil
		references: 	an IdentityDictionary(#(#Dictionary)->0 #(#JdmConnection)->0
#(#Jdm...etc...
		objects: 	an IdentityDictionary()
		currentReference: 	nil
		fwdRefEnds: 	an IdentityDictionary()
		blockers: 	an IdentityDictionary(('db' getDB reloadDB update)
('as yet unclassif...etc...
		skipping: 	an IdentitySet()
		insideASegment: 	false

ReferenceStream(DataStream)>>nextPut:
	Receiver: a ReferenceStream
	Arguments and temporary variables:
		anObject: 	1
		typeID: 	21
		selector: 	#writeInteger8:
		objectToStore: 	1
	Receiver's instance variables:
		byteStream: 	a DummyStream
		topCall: 	an ImageSegment
		basePos: 	47
		floatsAs32Bits: 	nil
		references: 	an IdentityDictionary(#(#Dictionary)->0 #(#JdmConnection)->0
#(#Jdm...etc...
		objects: 	an IdentityDictionary()
		currentReference: 	nil
		fwdRefEnds: 	an IdentityDictionary()
		blockers: 	an IdentityDictionary(('db' getDB reloadDB update)
('as yet unclassif...etc...
		skipping: 	an IdentitySet()
		insideASegment: 	false

[] in ReferenceStream(DataStream)>>nextPutAll:
	Arguments and temporary variables:
		aCollection: 	#(1 2)
		each: 	1

--- The rest of the stack ---
Array(SequenceableCollection)>>do:
ReferenceStream(DataStream)>>nextPutAll:
ReferenceStream(DataStream)>>writeArray:
ReferenceStream(DataStream)>>nextPut:
ClassOrganizer(Object)>>storeDataOn:
ReferenceStream(DataStream)>>writeInstance:
ReferenceStream(DataStream)>>nextPut:
[] in ReferenceStream(DataStream)>>nextPutAll:
Array(SequenceableCollection)>>do:
ReferenceStream(DataStream)>>nextPutAll:
ReferenceStream(DataStream)>>writeArray:
ReferenceStream(DataStream)>>nextPut:
ImageSegment(Object)>>storeDataOn:
ImageSegment>>storeDataOn:
ReferenceStream(DataStream)>>writeInstance:
ReferenceStream(DataStream)>>nextPut:
SmartRefStream>>instVarInfo:
[] in SmartRefStream>>nextPut:
ProgressInitiationException>>defaultAction
ProgressInitiationException(Exception)>>signal
ProgressInitiationException>>display:at:from:to:during:
ProgressInitiationException class>>display:at:from:to:during:
String>>displayProgressAt:from:to:during:
SmartRefStream>>nextPut:
StandardFileStream(ReadWriteStream)>>fileOutClass:andObject:
ImageSegment>>writeForExport:
UndefinedObject>>DoIt
Compiler>>evaluate:in:to:notifying:ifFail:
[] in TextMorphEditor(ParagraphEditor)>>evaluateSelection
BlockContext>>on:do:
TextMorphEditor(ParagraphEditor)>>evaluateSelection
TextMorphEditor(ParagraphEditor)>>doIt
[] in TextMorphEditor(ParagraphEditor)>>doIt:
TextMorphEditor(Controller)>>terminateAndInitializeAround:
TextMorphEditor(ParagraphEditor)>>doIt:
TextMorphEditor(ParagraphEditor)>>dispatchOnCharacter:with:
TextMorphEditor(ParagraphEditor)>>readKeyboard
TextMorphEditor>>readKeyboard
[] in TextMorphForEditView(TextMorph)>>keyStroke:
TextMorphForEditView(TextMorph)>>handleInteraction:fromEvent:
TextMorphForEditView>>handleInteraction:fromEvent:
TextMorphForEditView(TextMorph)>>keyStroke:
TextMorphForEditView>>keyStroke:
TextMorphForEditView(TextMorph)>>handleKeystroke:
KeyboardEvent>>sentTo:
TextMorphForEditView(Morph)>>handleEvent:
TextMorphForEditView(Morph)>>handleFocusEvent:
[] in HandMorph>>sendFocusEvent:to:clear:
PasteUpMorph>>becomeActiveDuring:
HandMorph>>sendFocusEvent:to:clear:
HandMorph>>sendEvent:focus:clear:
HandMorph>>sendKeyboardEvent:
HandMorph>>handleEvent:
HandMorph>>processEvents
[] in WorldState>>doOneCycleNowFor:
Array(SequenceableCollection)>>do:
WorldState>>handsDo:
-- and more not shown --