CRM 2011: Error while updating Organization database after Update Rollup 18

Hello,

We are testing a CRM 2011 update from Rollup 14 to Rollup 18. The update goes well, but the update of the organization not. I'm getting the following error:



With this error in the log file:

Update Organization with Id=74f03469-ce38-4058-8755-30ad90b4594d failed with Exception:
System.Exception: Action Microsoft.Crm.Tools.Admin.InstallDatabaseUpdatesAction failed. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.FormatException: Input string was not in a correct format.
   at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
   at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
   at Microsoft.Crm.Setup.MetadataPatchService.ProcessMetadataDiffFile(String targetRevision)
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at Microsoft.Crm.Setup.Database.DllMethodAction.Execute(Guid organizationId)
   at Microsoft.Crm.Setup.Database.DatabaseInstaller.ExecuteReleases(ReleaseInfo releaseInfo, Boolean isInstall)
   at Microsoft.Crm.Setup.Database.DatabaseInstaller.Install(Int32 languageCode, String configurationFilePath, Boolean upgradeDatabase, Boolean isInstall)
   at Microsoft.Crm.Setup.Database.DatabaseInstaller.InstallUpdate(String configurationFilePath, Boolean upgradeDatabase)
   at Microsoft.Crm.Setup.Common.Update.DBUpdateDatabaseInstaller.ApplyDBUpdates(Guid orgId)
   at Microsoft.Crm.Tools.Admin.InstallDatabaseUpdatesAction.ApplyDBUpdatesInternal(Guid orgId, String orgUniqueName, String releaseFilePath, Boolean ignoreErrors)
   at Microsoft.Crm.Tools.Admin.InstallDatabaseUpdatesAction.ApplyDBUpdates(Guid orgId, String orgUniqueName, OrganizationOperationType operationType)
   at Microsoft.Crm.Tools.Admin.InstallDatabaseUpdatesAction.Do(IDictionary parameters)
   at Microsoft.Crm.Setup.Common.CrmAction.ExecuteAction(CrmAction action, IDictionary parameters, Boolean undo)
   --- End of inner exception stack trace ---
   at Microsoft.Crm.Setup.Common.CrmAction.ExecuteAction(CrmAction action, IDictionary parameters, Boolean undo)
   at Microsoft.Crm.Setup.Common.Installer.Install(IDictionary stateSaver)
   at Microsoft.Crm.Tools.Admin.OrganizationOperation.Install(IDictionary stateSaver)
   at Microsoft.Crm.Tools.Admin.OrganizationOperation.Execute()
   at Microsoft.Crm.Tools.Admin.OrganizationDatabaseHotFixer.Execute()
   at Microsoft.Crm.Tools.Admin.ApplyDatabaseHotFixInstaller.ApplyDatabaseHotFix(IApplyDatabaseHotFixInfo applyDatabaseHotFixInfo)


I've searched the internet, but found nothing usefull.