C# Win Forms Access Violation Exception

Question

I keep getting the following error:

System.AccessViolationException was unhandled Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Source="FEDivaNET" StackTrace: at Diva.Handles.FEDivaObject.dropReference() at Diva.Handles.FEDivaObject.!FEDivaObject() at Diva.Handles.FEDivaObject.Dispose(Boolean ) at Diva.Handles.FEDivaObject.Finalize() InnerException:

Any ideas what the issue could be? - I'm using a library that is written in C++ and isn't designed for multithreading, yet I'm hammering it about 3000 times with requests every 6 minutes.

CODE

  delegate void SetTextCallback(string mxID, string text);
    public void UpdateLog(string mxID, string text)
    {
        //lock (thisLock)
        //{
            if (listBoxProcessLog.InvokeRequired)
            {
                SetTextCallback d = new SetTextCallback(UpdateLog);
                this.BeginInvoke(d, new object[] { mxID, text });
            }
            else
            {
                //Get a reference to the datatable assigned as the datasource.
                //DataTable logDT = (DataTable)listBoxProcessLog.DataSource;
                //logDT.Rows.Add(DateTime.Now + " - " + mxID + ": " + text);
                if (text.Contains("COMPLETE") || (text.Contains("FAILED")))
                {
                    if (progressBar1.Value <= progressBar1.MaxValue)
                    { progressBar1.Value += 1; }
                }

            }
        //}
    }

Baring in mind that even when the Lock and the DataTable weren't commented out, the error still occurred!

EDIT:

Unfortunately I don't have access to the C++ code, and the C# code is a wrapper around the functions.....basically the library is single threaded, and I'm guessing because it's unManaged that this is occuring.....suggestions?

Appdomains? - Would that work?