Contains a fix for Work Item: 2639. Thanks to JerryVienna for finding and reporting this issue.

DocX/Paragraph.cs

         /// <param name="trackChanges">Track changes</param>
         public void Replace(string oldValue, string newValue, bool trackChanges, RegexOptions options)
         {
-            MatchCollection mc = Regex.Matches(this.Value, oldValue, options);
+            MatchCollection mc = Regex.Matches(this.Value, Regex.Escape(oldValue), options);
             
             // Loop through the matches in reverse order
             foreach (Match m in mc.Cast<Match>().Reverse())