Dynamic memory is corrupt (Labwindows/cvi 2010)

Question

I have a multi threaded application....where I have a buffers allocated ineternally in the threads,,...A user interface is present to abort the therad execution.
Here is the code in one of the threads (NOTE: status is set by a user button to EXIT the program):
int EthernetDataStructureThread (void *functionData)
    CmtSetCurrentThreadPriority (2);
    EthernetData GetData={0}, *data=NULL;
    data = &GetData;
    /* Use a buffer to read the data from the queue which is coming from TCP read with fresh data */
    const void *BufferEth;
    int BytesRead=0;
    int BytesWritten=0;
    char ReadErrorMessage[256];
    BOOL bitset = FALSE;
    if ( (BufferEth = (EthernetData*)malloc(EthernetDataSize)) != NULL)
        while ( !status )
            BytesRead = CmtReadTSQData (Queue_TCPRead_EthernetData, BufferEth, EthernetDataSize, TSQ_INFINITE_TIMEOUT, 0);
            memcpy (data, BufferEth, EthernetDataSize);
            /* Empty the queue so that we don't have data in next time. */
            CmtFlushTSQ (Queue_TCPRead_EthernetData, TSQ_FLUSH_ALL, NULL);
            //Pass on the data to the Main thread
            BytesWritten = CmtWriteTSQData (Queue_EthernetData_Main, BufferEth , EthernetDataSize, 1, NULL);
            if ( BytesWritten != EthernetDataSize)
                 free(BufferEth);
                BufferEth = NULL;
                exit(0);
            Delay(0.02);
        if (status && !bitset)
            free(BufferEth);
            BufferEth = NULL;
            bitset = TRUE;
    return 0;
My problem is: free(BuffEth) always says Dynamic Memory is corrupt......When I put a breakpoint and keep seeing the resource tracking window, I can see it getting executed fine as the resource tracking window greys out the memory block....but then suddenly free wants to exceute again...and causes the "dynamic memory is corrupt" error.
I am using LABWINDOWS /CVI 2010 SP1 in WinXP.
Please help me ASAP....very much appreciated.
Regards
NITIN
-Nharish

Answer 1

Thank you for your reply Jackie.
I am calling Free only once...there is an If condition there.
See the attched video for my problem...Free frees the memory block (see the greyed out portion in resource tracking window but still the statement controls remains there and free executes again, throwing error).
Do you  think it is some sort of bug in LABWINDOWS.
See the attached video.
-Nharish
Attachments:
FreeproblemLabwindows.avi ‏4781 KB