Donald,
After consulting with a number of Duxbury users, our recommendation would be to contact Duxbury Support. Since there are numerous versions of DBT, Swift, and MathType, we are not equipped to resolve the issue you are experiencing. You may email them at support@duxsys.com or call 1-978-692-3000. Additionally, you may want to join the DuxUser Discussion Group. You can subscribe to duxuser by sending a blank message to duxuser-request@freelists.org with "subscribe" in the subject line. I hope this information leads you to the answer you are searching for.