Just to clarify that - it is not e-ons SDK, it is Bondwares. No SDK from them, no compatibility with later versions. And now it is too late for an update.

DLOIS_1791 is a generic error message that tells only that a generic problem in loading the file has happened. Nothing more.

And indeed, I think the trial version will not do the trick here. But in this I might be wrong.

My guess is still that the problem might come from the fact that the pz3s that someone tries to load that has Poser 11 installed and directed Vue correctly to it but uses later versions of Poser to generate those, contains features that are newer than Poser 11. And/or tries to use import features that are no longer compatible.

For a test I recommend to load an old Poser character without any special settings and use the basic import settings - no re-posing, no Poser shader tree and only frame 0 and not an entire Poser animation. That is interesting to see, if that works or not, here it does.

One day your ship comes in - but you're at the airport.