DAMAGE: After Normal Block

In my project I have a problem.

There is a CByteArray in it.
When there is a small amount of data in it, everything is working well.
But whwen there are more then +- 1900 bytes in it

and I try to delete this array with,
delete pArray

I get the message "Damage: after Normal Block (#561) at ......"

In the debugger I see <DbgHeap.c> :
------------------------

if (!CheckBytes(pbData(pHead) + pHead->nDataSize, _bNoMansLandFill, nNoMansLandSize))
_RPT3(_CRT_ERROR, "DAMAGE: after %hs block (#%d) at 0x%08X.\n",
szBlockUseName[_BLOCK_TYPE(pHead->nBlockUse)],
pHead->lRequest,
(BYTE *) pbData(pHead));




My Call stack is like this,


_free_dbg_lk(void * 0x00e20ae0, int 1) line 1033 + 60 bytes
_free_dbg(void * 0x00e20ae0, int 1) line 970 + 13 bytes
operator delete(void * 0x00e20ae0) line 282 + 11 bytes
CByteArray::SetSize(int 0, int -1) line 61 + 18 bytes
CByteArray::RemoveAll() line 22 + 19 bytes
CDataPacketText::~CDataPacketText() line 127
CDataPacketText::`scalar deleting destructor'(unsigned int 1) + 15 bytes



Does anyone know what's happening here