Ok, I thought I was lost before, and now it is worse.
There are two versions of the driver, a 1.3 and a 1.5:
both contain both the x86 and x64 version, but you recompiled from sources?
Even if it seems like I am asking you random questions, they are not as random as they seem, they are an attempt to understand the issue (and/or make it more clear to other members reading the topic), it would probably be of help if you could actually answer them.
If you have two versions of the SAME driver version, pre-compiled, i.e. "as downloaded from Sourceforge" in the SAME version od OS, and the x86 version "doesn't work" whilst the x64 "works", post the screenshots of BOTH versions (the one that is working and the one that is not) of device manager sorted "by connection".
Can you try the x86 version on a Windows 7 x86?
I mean, is the issue Windows 2003+Nvme.sys+x86 only or is it also Winfows7+Nvme.sys+x86 (but not Windows 7+nvme.sys+x64)?