Since there have been no updates to this software in well over a year or two I assumed it was as good as dead! Finally, these forums have confirmed this to be true.
I am another unhappy customer - that never did get it to work. I've got about 80 lost hours into this thing, and finally packed it in due to the numerous errors messages. After configuring the server with all the tips/tricks provided by the people at Interakt - it still produced numerous errors, and only worked about 25% of the time (on two completely different servers).
I replaced it with PHPLIST http://www.phplist.com (I will push this product now that the MX Newsletter is officially dead) which is free of charge, and is much more stable than MX Newsletter ever was. It's more difficult to understand - and setup, but it works.
In the end - I love Interakt products, I think they are great. This one was a DUD but I guess every company has one of those on occasion. I like the idea another person had on these posts - "Interakt should provide a voucher to all licensed MX Newsletter Users". It wouldn't cost them a thing, and may save the loss of many unhappy clients.
Support was terrible with this product. It was continually pushed aside while other products were upgraded. We continued to be told "It will be done in a future release". The future release died at Ver 1.01, hardly given any type of a chance.
I will continue to support the company - but I will NOT be quick to buy new products without reading the support forums for months prior to committing.
R.I.P MX Newsletter - Your like a dog that was locked in the basement and never fed.