China DOS Union

After booting with an MSDOS7.1 boot disk and running some other programs, when I run PQMAGIC again there is no response at all, that is, PQMAGIC will not start. In this kind of situation, what is usually the problem? Is it not enough conventional memory, or not enough environment variables, or some other reason? The CONFIG.SYS configuration is as follows:
[COMMON]
device=himem.sys /testmemff
files=60
buffers=20
dos=high,umb
stacks=9,256
devicehigh=ramdrive.sys /E 3096
lastdrive=z

Maybe it's an EMM386.exe problem (although the “[COMMON]” section doesn't load it, it should be loaded somewhere else)? PQMagic is not recommended to run under DOS with Emm386.exe loaded.

EMM386 is not loaded, so dos=umb has no effect. Also, what about autoexec.bat?
Try skipping config.sys and autoexec.bat and doing a clean boot.

EMM386 isn't loaded anywhere else either. But on some computers it runs without any problem, which is really strange.