I am pretty sure the problem is related to the Windows Taskbar position and size.
I followed your instructions. I first tried reinstalling DVDFAB by downloading the install package new from the internet. I then ran the install. When DVDFAB started after the update, I still had the corruption.
So I then did the complete uninstall as described in your guide. I did every piece, including the registry deletions. I rebooted. I then downloaded a new copy of the DVDFAB 18.104.22.168 install package from the web site. I ran the install. I input my registration key. And then when DVDFAB came back up, it still had the same exact corruption.
I still think it's the taskbar. If I move my taskbar to the bottom of the screen, which I guess is the default and how most people leave it, then start DVDFAB, the window title displays ok. I get no screen corruption. If I move the taskbar back to the top of my screen then start DVDFAB, I get the corruption. The text displays lower than it should. corrupting part of the window.
I can also get the text to display improperly and cause different corruption if I move my taskbar to the left side of my screen. With the taskbar on the left side of the screen, when I start DVDFAB the text appears on the window title area, but pushed off to the right. That causes corruption over the buttons in the upper-right corner of the DVDFAB window. With the taskbar on the right side of the screen, when I start DVDFAB the text appears normally.
So I get the corrution if my Windows taskbar is on the top or left side of my screen. I also tried installing a brand new first time install of DVDFAB on another PC. It exhibited the exact same problems. So this corruption wasn't unique to my main PC.
Another thing that indicates it's related to the taskbar is that the corruption moves based on how thick the taskbar is. My taskbar is set to 2 "rows" thick -- or whatever you want to call it. If I unlock the taskbar and drag it thicker, to 3 or 4 or 5 rows thick, then start DVDFAB, the text and corruption move further down in the window.
So I can easily make the corruption appear or not, and move, by simply adjusting the Windows taskbar location and size.
I'm running Windows XP Pro SP3. It's pretty easy for me to reproduce all this corruption. I can take screenshots of the different corruption, if anyone wants.