"Block just read from file is not a valid heap block" Error

I have a table with 38 fields (and 2 nxtBlobWideMemo).

To change record I use SQL like this (in Delphi XE using nxQuery component):

DELETE FROM HIP0051R WHERE hvCODIGO = :CODIGO;
:
INSERT INTO HIP0051R (Field1, Field2,...FieldN)
VALUES (:Field1, :Field2, .. :FieldN);
:

Don´t occurs any error in write but when accessing the same record I
received the error:

"Block just read from file is not a valid heap block"

If I read same record again I don´t receive any error (this error occurs
only in first access after record edit).

I tried to Pack Table (in E.M.) but error persists.

============================
Exception Log:
Time: [10197859] 29/06/2012 10:44:22
ExceptionInfo: nil
Exception: EnxCachedHeapEngineException
Message: NexusDB: Block just read from file is not a valid heap block
[Z:\Hipercusto12_DXE\Banco Teste\HIP0051R.nx1, block 2520] [$3C38/15416]
Filesize: 8240384
Filedate: 2012-03-04 03:03:34
Computer: QUADCORE
User: Samuel
ThreadID: 1232
ProcessID: 2732
Version: 3,1004
Client: C:\Temp\HIPERTEMP\Hipercusto.exe;Size:47370752;Dat e:2012-06-29
10:40:42;Computer:QUADCORE;User:Samuel
SessionID: 4269383696
Connected From: 192.168.0.22:56991
--------------------------------------------------------------
Callstack (Frames):
[008F298C] nxseHeapEngineCached.TnxCachedHeapEngine.heReadBlo ck (Line
877, "nxseHeapEngineCached.pas")
[008F1C49] nxseHeapEngineCached.TnxCachedHeapEngine.GetSegmen t (Line
616, "nxseHeapEngineCached.pas")
[008D7D19] nxseBlobEngineSegmented.TnxSegmentedBlobEngine.Get BlobLength
(Line 918, "nxseBlobEngineSegmented.pas")
[00622107] nxsrBlobHandlerCaching.TnxCachingBlobHandler.BlobG etLength
(Line 643, "nxsrBlobHandlerCaching.pas")
[00643ED5] nxsrServerEngine.TnxServerTableCursor.sbcBlobGetLe ngth (Line
12083, "nxsrServerEngine.pas")
[0063D27B] nxsrServerEngine.TnxBlobLinkHandler.BlobLinkGetLen gth (Line
9393, "nxsrServerEngine.pas")
[008D8073] nxseBlobEngineSegmented.TnxSegmentedBlobEngine.Get BlobLength
(Line 969, "nxseBlobEngineSegmented.pas")
[00620B33]
nxsrBlobHandlerPassthrough.TnxPassthroughBlobHandl er.BlobGetLength (Line
246, "nxsrBlobHandlerPassthrough.pas")
[00643ED5] nxsrServerEngine.TnxServerTableCursor.sbcBlobGetLe ngth (Line
12083, "nxsrServerEngine.pas")
[0063DA23] nxsrServerEngine.TnxServerBaseCursor.BlobGetLength (Line
9602, "nxsrServerEngine.pas")
[00690EAE]
nxchCommandHandler.TnxServerCommandHandler.nmCurso rBlobGetLength2 (Line
1193, "nxchCommandHandler.pas")
[0068E155] nxchCommandHandler.TnxServerCommandHandler.bchProc ess (Line
640, "nxchCommandHandler.pas")
[00551AA9] nxllTransport.TnxBaseTransport.btProcess (Line 1824,
"nxllTransport.pas")
[0065B536]
nxptBasePooledTransport.TnxBasePooledTransport.btP ayloadReceived (Line
3120, "nxptBasePooledTransport.pas")
[0065B1FF]
nxptBasePooledTransport.TnxBasePooledTransport.btM essageReceived (Line
2998, "nxptBasePooledTransport.pas")
[00662F05] nxtwWinsockTransport.TnxWinsockServerConnection.Io Completed
(Line 668, "nxtwWinsockTransport.pas")
[00662E6C] nxtwWinsockTransport.TnxWinsockServerConnection.Io Completed
(Line 647, "nxtwWinsockTransport.pas")
[00659162] nxptBasePooledTransport.TnxBaseServerThread.InnerE xecute
(Line 2100, "nxptBasePooledTransport.pas")
[0054D684] nxllThread.TnxInternalInitThread.DoExecute (Line 674,
"nxllThread.pas")
[0054D41B] nxllThread.TnxThread.Execute (Line 478, "nxllThread.pas")
[00460A96] Classes.ThreadProc
[00407DEC] System.ThreadWrapper
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