Thanks, mpack. Lots to update here, so bear with me.
Because of the other problems I just had with the display, I've set up a new vm running Windows 98SE (just because it's easier than setting up Win95), and I installed the HD display driver provided by FranceBB in the thread scottgus1 pointed me to. I did that before you replied, so I set it up with 512 Mb RAM (as instructed here
https://i12bretro.github.io/tutorials/0070.html) and I gave the video card 64 Mb (as instructed by FranceBB.) The display settings are True Color 32 and 1920x1080.
I then installed the software and it gave me the same error: expecting 8 Mb RAM, it finds 0 Mb. However, the installation was able to continue successfully. The only issue is that when the program runs, it's a bit slow/laggy, and the audio starts and stops, like it's buffering on a really slow connection (which is problematic because the program contains narration). Additionally, the program goes full screen, but the display of the program is limited to a small area in the centre of the screen. (So there's a large black border surrounding it.)
Having seen your reply, I then changed the VM RAM to 16 Mb. It does something a little weird when starting up now (after the Win98 splash screen, there's a glitchy-looking partial Oracle logo in the upper right), but then the OS runs normally. When I launch the software, it's exactly as described before (laggy/skipping audio/small display).
My next thought was that maybe the lag is caused by the software running from a physical CD-ROM attached to the host and fed in to the guest, so I used AnyBurn to copy the CD-ROM to an ISO file which I can attach directly to the virtual CD drive. Unfortunately, that didn't resolve any of the problems, either.
Then I uninstalled the software and reinstalled it. This time, when it ran the system check, it asked for 8 Mb RAM and it found 16, so your advice works for that issue. Nevertheless, when running the software, it's the same as before... laggy, skipping, small display.
In summary, reducing the available RAM on the VM did solve the installation system check issue, yet there are still some other problems preventing the software from running correctly. I realize that those issues, and the fact that I'm now working in Windows 98, go beyond the topic of this thread, but perhaps for continuity it's better not to start a new thread. (Or should I?)
Thanks again for your help.