I've been testing what you describe and can't replicate your problem.
The MTU advert only displays when there are no entries ticked to display in the list and you still have the marquee activated.
Try turning it off for now by ticking the box bottom left "Hide Marquee in all views" press apply and OK.
When this version installs it also places a HosterPrior icon on your desktop that should be the version you had before, (click on Help About to check)have you tried that and is that having the same problem ?
As you have been using this function for some time I'm sure you understand how it works so I can only think there must be something wrong with your download.
When you downloaded 5.07 did you start the download from the message that pops up after Hoster starts and informs you that a new version is available ?
I ask this as I noticed that after downloading this way and selecting the download folder there is no information telling you it is downloading until it completes after which it informs you to close Hoster so that it can install.
If you do anything before seeing this message it seems you don't get a full download.
So what I should try is delete your original downloaded "hoster507.05setup.exe" (if you don't delet it it still doesn't do a full download) file if you saved it. Reinstall your previous version of Hoster and check that is working correct then do a fresh Download and install of 5.07.
You can just re-download 5.07 and install it if you like but that will make your HosterPrior the one you have now that isn't working right
If the problem still exists after doing all the above I should submit a support ticket.