Congratulations. It sounds like you didn't quite follow instructions about upgrading though. On the Dataviz download page, there's a place to enter your serial number to get to the free upgrade area. There's also a link that tells you how to find your serial number. It sounds like you just downloaded the latest trial version.
You have two choices. The first is to go to the free download area and get the T|E bugfix upgrade. You can then delete the trial version of DTG and then install the T|E upgrade. If I remember right, DTG is in ROM on the T|E so deleting the trial version should still leave the original version intact and allow to hotsync the update. If it's not in ROM, it will be on your CD and you'd have to reinstall from the CD and then apply the upgrade.
The second choice, if you like the trial version, is to buy it. It does have some nicer features than the DTG version 6.x that came with the T|E.
In terms of avoiding things like this in the future, always assume that any piece of hardware or software you buy has bugs and that the manufacturer's will release updates to fix them when the beta testers (which means retail customers now) report them. Check back at the hardware and software web sites on a regular basis to check for updates. It's also a good idea to peruse forums like this regularly since widespread problems are usually posted very quickly.