>had an empty value for the file name, like "\.directb2s"
I had exactly the same problem. Also mainly the same tables as described above. New, modern, big tables.
All worked fine directly from VPX, failed from PinballX. All worked without fullscreen.
If I tried from VPX and THEN directly from PinballX it always works, but other tables fails. Always the last played table in VPX also worked in PinballX. So I thought it is something with Registry or so.
I renamed the tables and backglass, to simple names like "monster". Only lowercase, only characters, 8 char or less, good old DOS rules. Did not helped always.
I opened the direct2bs files (they are in fact XML) and entered there the same names. Helped with some, not with all.
I entered the ROM names. Helped with some more.
Sometimes I thought it was just that, then it failed with the next table again.
It was more trial&error mixed with magic as real fixing.
Because of Registry difference (comparing after launching directly from VPX and comparing with PinballX) I tried to launch PinballX as admin. That helped! But I always got that stupid admin dialog. So I removed the flag again - and it still worked. No idea why.
at least, at the end all tables worked except Lord of the Rings. I used an older, smaller backglass and now also that works. Currently all tables works for me... Happy again. Needed 4 weeks.
It is a combination of large tables and large backglass, launched from Pinballx and not directly.
btw, it is an i5 with 8 GB Ram, Windows 10, 2 screens + DMD.
So for all frustrated with the same issue: sorry, no clear help, but at least, you are not alone. And it seems to be solveable, don't give up.
Be careful, it could be several issues at the same time. Once i installed a new Elvira and that also failed, which always worked before. I needed a while to see I had a typo in the name, so table/backglass had different names and it was normal that this failed. But if you are already frustrated, you might miss that easy.
Every time when I thought I found the reason, the same trick failed with another table. But table by table, more and more worked, so don't give up.
I think it was worth the time. I had so much stutter before, was close to spend a fortune and purchase a 1080 card, just to be able to play without that stutter. Now (I have a 970) everything is fine, fast, super.
Fullscreen mode is great, thousand thanks to the developers!