Metaballs problem with b27.1

hi,
i get EClrException: Object reference not set to an instance of an object (null pointer exception) and a red node. details:

Stack list, generated 3/22/2012 10:47:16
[005918F1](005918F1){vvvv.exe    } ClrUtils.ClrCheck (Line 1048, "ClrUtils.pas" + 2)
[00650157](00650157){vvvv.exe    } PluginNodes.TMPluginWrapperNode.EvaluateV1Plugin (Line 298, "PluginNodes.pas" + 1)
[0064FF66](0064FF66){vvvv.exe    } PluginNodes.TMPluginWrapperNode.Evaluate (Line 257, "PluginNodes.pas" + 24)
[006518D5](006518D5){vvvv.exe    } PluginNodes.TMPluginWrapperNode.CalculateNodeAndOutputSliceCounts (Line 936, "PluginNodes.pas" + 8)
[00686770](00686770){vvvv.exe    } Graph.TMBasicNode.Prepare (Line 1145, "Graph.pas" + 20)
[006886A9](006886A9){vvvv.exe    } Graph.TMPin._Prepare (Line 2345, "Graph.pas" + 4)
[00688605](00688605){vvvv.exe    } Graph.TMPin.GetSliceCount (Line 2310, "Graph.pas" + 1)
[006141F4](006141F4){vvvv.exe    } MultiControl.TMMultiControl.SetComponentValue (Line 512, "MultiControl.pas" + 4)
[00612985](00612985){vvvv.exe    } IOValueComponent.TMIOValueComponent.ValidatePaintControl (Line 1097, "IOValueComponent.pas" + 1)
[005A5E46](005A5E46){vvvv.exe    } IOViewComponent.TMIOComponent.UpdateView (Line 456, "IOViewComponent.pas" + 7)
[0042DE7A](0042DE7A){vvvv.exe    } Contnrs.TObjectList.GetItem
[00613B76](00613B76){vvvv.exe    } MultiControl.TMMultiControl.UpdateControl (Line 357, "MultiControl.pas" + 3)
[006164AC](006164AC){vvvv.exe    } Inspektor.TMInspektor.UpdateView (Line 535, "Inspektor.pas" + 26)
[0061734C](0061734C){vvvv.exe    } InspektorNode.TMInspektorNode.UpdateViewCB (Line 57, "InspektorNode.pas" + 2)
[0069B6E5](0069B6E5){vvvv.exe    } Events.TMEvent.Call (Line 403, "Events.pas" + 11)
[00698BA2](00698BA2){vvvv.exe    } MainLoop.TMMainLoop.DoTimer (Line 215, "MainLoop.pas" + 34)
[00508BC6](00508BC6){vvvv.exe    } IdleTimer.TMIdleTimer.AppIdle (Line 165, "IdleTimer.pas" + 46)
[00480B35](00480B35){vvvv.exe    } Forms.TApplication.Idle
[0047FFA7](0047FFA7){vvvv.exe    } Forms.TApplication.HandleMessage
[0048028F](0048028F){vvvv.exe    } Forms.TApplication.Run