*sigh* I'm back again. Same program. Different problem.

private void executeToolStripMenuItem_Click(object sender, EventArgs e)
            string aaa = String.Format(richTextBoxEditor.ToString()); /*<-- Guessing that this is redundant */
            lua.DoString(aaa); //<-- problem code

When I attempt to execute the Lua code in the textbox, it crashes the program. Wat do?

Fix'd. Used a streamwriter to create a temporary text file holding the data, and then executing that data from the file. Sorry for wasting your time.