Error: Name not found: Base

Ciao, i work with a Pharo 2.0 20628 image. I report error: [Pharo-dev] MessageNotUnderstood: SmallInteger>>isEmpty to <pharo-dev(a)lists.pharo.org> After i first do: ( ConfigurationOfSeaside3 project version: '3.1.0') load and test it ( it work fine ). Now the ((Smalltalk at: #ConfigurationOfQCMagritte) project version: '0.2') load: #( 'Demo' ) erase the error : MetacelloMCVersionSpec(Object)>>error: MetacelloMCVersionSpec>>resolveToLoadableSpec:forMap:packages: in Block: [^ self error: 'Name not found: ' , aString] MetacelloMCVersionSpec>>packageNamed:forMap:ifAbsent: MetacelloMCVersionSpec>>resolveToLoadableSpec:forMap:packages: MetacelloMCVersionSpec>>resolveToLoadableSpecs:map: in Block: [:req | (self... Set>>do: MetacelloMCVersionSpec>>resolveToLoadableSpecs:map: MetacelloMCVersionSpecLoader>>resolveToLoadableSpecs MetacelloMCVersionSpecLoader>>load MetacelloMCVersion>>executeLoadFromArray: MetacelloMCVersion>>fetchRequiredFromArray: in Block: [:dict | ^ self executeLoadFromArray: anArray] MetacelloPharoPlatform(MetacelloPlatform)>>useStackCacheDuring:defaultDictionary: in Block: [^ aBlock value: dict] BlockClosure>>on:do: MetacelloPharoPlatform(MetacelloPlatform)>>useStackCacheDuring:defaultDictionary: MetacelloMCVersion>>fetchRequiredFromArray: in Block: [self versionSpec loader: newLoader.... BlockClosure>>ensure: MetacelloMCVersion>>fetchRequiredFromArray: in Block: [[self versionSpec loader: newLoader.... MetacelloPharoPlatform>>do:displaying: in Block: [aBlock value] BlockClosure>>ensure: RPackageSet class>>withCacheDo: MetacelloPharoPlatform>>do:displaying: in Block: [:bar | ... BlockClosure>>cull: Job>>run in Block: [result := block cull: self] BlockClosure>>on:do: Job>>run in Block: [self prepareForRunning.... BlockClosure>>ensure: Job>>run MorphicUIManager(UIManager)>>displayProgress:from:to:during: ByteString(String)>>displayProgressFrom:to:during: MetacelloPharoPlatform>>do:displaying: I wrong something ? I can load QCMagritte with Seaside 3.1.0 ? Thanks for any considerations Dario