Sorry for the late reply, but I made a new installation of Windows NT4, and strangely enough, it worked, the browser did not crash at all. Strangely enough, I set the virtual memory by around 815 MB.
The Retrozilla version I installed on the new NT4 installation in Virtualbox is Version 2.1, as seen in this screenshot I took.
PS: I got the SeaMonkey port of the "Orbit" theme, applied in this browser, it looks pretty cool.