here insert explanation of what you were doing, suspect changes you've made and so forth. 25 May 2010 1:03:21 pm VM: unix - x86_64 - linux - Squeak3.10.2 of '5 June 2008' [latest update: #7179] Image: Pharo-1.0 [Latest update: #10517] SecurityManager state: Restricted: false FileAccess: true SocketAccess: true Working Dir /var/www/seaside/register Trusted Dir /var/www/seaside/register/secure Untrusted Dir /var/www/seaside/register/My Squeak UndefinedObject(Object)>>doesNotUnderstand: #binary Receiver: nil Arguments and temporary variables: aMessage: binary exception: MessageNotUnderstood: receiver of "binary" is nil resumeValue: nil Receiver's instance variables: nil ReferenceStream(DataStream)>>setStream: Receiver: <<error during printing>> Arguments and temporary variables: aStream: nil Receiver's instance variables: byteStream: nil topCall: nil basePos: nil references: nil objects: nil currentReference: nil fwdRefEnds: nil blockers: nil skipping: nil insideASegment: nil ReferenceStream>>setStream: Receiver: <<error during printing>> Arguments and temporary variables: aStream: nil Receiver's instance variables: byteStream: nil topCall: nil basePos: nil references: nil objects: nil currentReference: nil fwdRefEnds: nil blockers: nil skipping: nil insideASegment: nil ReferenceStream class(DataStream class)>>on: Receiver: ReferenceStream Arguments and temporary variables: aStream: nil Receiver's instance variables: superclass: DataStream methodDict: a MethodDictionary(#beginInstance:size:->a CompiledMethod(117: Refe...etc... format: 150 instanceVariables: #('references' 'objects' 'currentReference' 'fwdRefEnds' 'bl...etc... organization: ('reading' beginReference: getCurrentReference maybeBeginReferenc...etc... subclasses: {SmartRefStream} name: #ReferenceStream classPool: a Dictionary(#RefTypes->an OrderedCollection(0 0 0 0 1 1 1 1 1 0 1 0...etc... sharedPools: nil environment: Smalltalk category: #'System-Object Storage' traitComposition: nil localSelectors: nil ReferenceStream class>>on: Receiver: ReferenceStream Arguments and temporary variables: aStream: nil Receiver's instance variables: superclass: DataStream methodDict: a MethodDictionary(#beginInstance:size:->a CompiledMethod(117: Refe...etc... format: 150 instanceVariables: #('references' 'objects' 'currentReference' 'fwdRefEnds' 'bl...etc... organization: ('reading' beginReference: getCurrentReference maybeBeginReferenc...etc... subclasses: {SmartRefStream} name: #ReferenceStream classPool: a Dictionary(#RefTypes->an OrderedCollection(0 0 0 0 1 1 1 1 1 0 1 0...etc... sharedPools: nil environment: Smalltalk category: #'System-Object Storage' traitComposition: nil localSelectors: nil ReferenceStream class(DataStream class)>>newFileNamed: Receiver: ReferenceStream Arguments and temporary variables: aString: '/var/www/seaside/register/PatagoniaBackup/register/esug2010.1' strm: nil Receiver's instance variables: superclass: DataStream methodDict: a MethodDictionary(#beginInstance:size:->a CompiledMethod(117: Refe...etc... format: 150 instanceVariables: #('references' 'objects' 'currentReference' 'fwdRefEnds' 'bl...etc... organization: ('reading' beginReference: getCurrentReference maybeBeginReferenc...etc... subclasses: {SmartRefStream} name: #ReferenceStream classPool: a Dictionary(#RefTypes->an OrderedCollection(0 0 0 0 1 1 1 1 1 0 1 0...etc... sharedPools: nil environment: Smalltalk category: #'System-Object Storage' traitComposition: nil localSelectors: nil ReferenceStream class>>newFileNamed:do: Receiver: ReferenceStream Arguments and temporary variables: aName: '/var/www/seaside/register/PatagoniaBackup/register/esug2010.1' aBlock: [closure] in [] in PatPatagoniaFileDatabase>>saveRepository file: nil Receiver's instance variables: superclass: DataStream methodDict: a MethodDictionary(#beginInstance:size:->a CompiledMethod(117: Refe...etc... format: 150 instanceVariables: #('references' 'objects' 'currentReference' 'fwdRefEnds' 'bl...etc... organization: ('reading' beginReference: getCurrentReference maybeBeginReferenc...etc... subclasses: {SmartRefStream} name: #ReferenceStream classPool: a Dictionary(#RefTypes->an OrderedCollection(0 0 0 0 1 1 1 1 1 0 1 0...etc... sharedPools: nil environment: Smalltalk category: #'System-Object Storage' traitComposition: nil localSelectors: nil [] in PatPatagoniaFileDatabase>>saveRepository Receiver: a PatPatagoniaFileDatabase Arguments and temporary variables: fileName: '/var/www/seaside/register/PatagoniaBackup/register/esug2010.1' Receiver's instance variables: conference: a PatConference entryPoint: 'register/esug2010' lock: a Semaphore(a Process in [] in Semaphore>>critical: a Process in [] in Se...etc... [] in Semaphore>>critical: Receiver: a Semaphore(a Process in [] in Semaphore>>critical: a Process in [] in Semaphore>>critical...etc... Arguments and temporary variables: <<error during printing> Receiver's instance variables: firstLink: a Process in [] in Semaphore>>critical: lastLink: a Process in [] in Semaphore>>critical: excessSignals: 0 BlockClosure>>ensure: Receiver: [closure] in Semaphore>>critical: Arguments and temporary variables: aBlock: [closure] in Semaphore>>critical: returnValue: nil b: nil Receiver's instance variables: outerContext: Semaphore>>critical: startpc: 38 numArgs: 0 Semaphore>>critical: Receiver: a Semaphore(a Process in [] in Semaphore>>critical: a Process in [] in Semaphore>>critical...etc... Arguments and temporary variables: <<error during printing> Receiver's instance variables: firstLink: a Process in [] in Semaphore>>critical: lastLink: a Process in [] in Semaphore>>critical: excessSignals: 0 PatPatagoniaFileDatabase>>saveRepository Receiver: a PatPatagoniaFileDatabase Arguments and temporary variables: Receiver's instance variables: conference: a PatConference entryPoint: 'register/esug2010' lock: a Semaphore(a Process in [] in Semaphore>>critical: a Process in [] in Se...etc... [] in PatPatagoniaFileDatabase>>takeSnapshot Receiver: a PatPatagoniaFileDatabase Arguments and temporary variables: Receiver's instance variables: conference: a PatConference entryPoint: 'register/esug2010' lock: a Semaphore(a Process in [] in Semaphore>>critical: a Process in [] in Se...etc... [] in BlockClosure>>newProcess Receiver: [closure] in PatPatagoniaFileDatabase>>takeSnapshot Arguments and temporary variables: Receiver's instance variables: outerContext: PatPatagoniaFileDatabase>>takeSnapshot startpc: 45 numArgs: 0 --- The full stack --- UndefinedObject(Object)>>doesNotUnderstand: #binary ReferenceStream(DataStream)>>setStream: ReferenceStream>>setStream: ReferenceStream class(DataStream class)>>on: ReferenceStream class>>on: ReferenceStream class(DataStream class)>>newFileNamed: ReferenceStream class>>newFileNamed:do: [] in PatPatagoniaFileDatabase>>saveRepository [] in Semaphore>>critical: BlockClosure>>ensure: Semaphore>>critical: PatPatagoniaFileDatabase>>saveRepository [] in PatPatagoniaFileDatabase>>takeSnapshot [] in BlockClosure>>newProcess