Instron 8800 Control Timeout Issue using NI-VISA (VISA Error code: -1073807339) in C# Application

I've written an application using C# which queries an Instron 8800 controller (very old controller).  While the program is running I get seemingly random timeout errors (error code defined in title), which eventually lead to an EABO error.  The program will typically start and query fine for 2 - 3 iterations, and then give the aforementioned timeout error.  It will then work for another few iterations and timeout again.

I've adjusted bus timing values per Instron's suggestion, but to no avail--does anyone have any ideas?  I've attemped using both the GpibInterface and MessageBasedSession classes.

Code below:

using NationalInstruments.VisaNS;

namespace niVISAInstronTest
{
 public partial class Form1 : Form
 {
 private MessageBasedSession mbSession;
 private GpibInterface instron_GPIB;

private void button1_Click(object sender, EventArgs e)
{
timer_Cyclic.Enabled = true;
textBox1.Enabled = false;
button1.Enabled = false;
GPIB_Address = textBox1.Text;
instron_GPIB = new GpibInterface(GPIB_Address, AccessModes.NoLock, 0, false);
instron_GPIB.SendEndEnabled = true;
instron_GPIB.Timeout = 10000;

}
private void timer_Cyclic_Tick(object sender, EventArgs e)
{
WriteToConsole(Query("Q210").ToString());
}
/// <summary>
/// 500ms timeout seems to work best so far
/// </summary>
/// <param name="query"></param>
/// <returns></returns>
public double Query(string query)
{
double response = -1;
try
{

//response = double.Parse(mbSession.Query(query));
instron_GPIB.Write(query);
string response_s = instron_GPIB.ReadString();
response = double.Parse(response_s);
return response;
}
catch (Exception EX)
{
WriteToConsole(EX.GetBaseException().ToString());
}

return response;
}
public void WriteToConsole(string msg)
{
textBox_Console.Text += Environment.NewLine + msg;
textBox_Console.SelectionStart = textBox_Console.TextLength;

textBox_Console.ScrollToCaret();
}