Hi there, @milmac.
Thanks for letting us know this has been your concern also in QuickBooks. I have information to add about the error 3371 you're getting when trying to download the software.
Please contact directly to our QuickBooks Desktop Care Team, so you'll also be added as one of the affected users. Rest assured I'll get back to you or one of my colleague here in the Community space once this issue is resolved.
On the other hand, consider upgrading QuickBooks to the latest version since you have a unsupported version. If you wish to, just refer to the link provided by my colleague @BettyJaneB on this thread.
To reach out support, follow the steps provided by my colleague @Angelyn_T.
For future references, check out the following articles below:
This information should get you in the right direction. If you have other questions aside from this, feel free to post your comment below. I'm always here to help. Have a great rest of the week.