I have just gone through a debug session with Leo from technical support and he found the problem. I don't know if he was able to install the missing samples (Which I am guessing is part of the mellotron instrument which is included IF you bought the instrument - At least that's what I am thinking) but, he was able to send me a demo download which should install the missing samples. I'm still waiting for the download to complete and once done, I'll try it out to ensure that it works. Will let you know as soon as possible.
In the mean time, you could send an email to technical.support@arturia.com
In the meantime, try doing the following if the problem was fixed:
Go to: C:\programdata\arturia\presets and delete the file: Vangelis Tribute II.json (Make sure Analog lab is not open)
Next, start Analog Lab then right click on the Vangelis Tribute II bank and select DELETE.
Once done, go back to the store and click on the tribute II selection and it should start downloading the bank again.
If they fixed the problem, it should work fine.
If not, ask technical.support@arturia.com and let them know that the bank needs the missing samples for the Mellotron and that another user downloaded a demo sample to make it work.
I was also told that once the demo version of the mellotron was installed, to delete it (uninstall I suppose)
In the meantime, I guess you could download the mellotron instrument then try it out.
Update: After installing the mellotron instrument then removing it, the presets do work. TADAH!
Now, the instrument shows that the preset with the missing samples is called KEYS instead. Problem solved.