If you don't need Distiller 4.x or 5.x for a specific legacy hardware reason, stop searching. Here are modern, free alternatives that do the same job better and safer:
You understand: Installing software from 1999 on a networked computer is dangerous. Distiller 4.x and 5.x have known, unpatched vulnerabilities: adobe acrobat distiller 4.x 5.x free download
There is no official, legal "free download" for standalone Distiller 4.x or 5.x from Adobe. If you don't need Distiller 4
There are thousands of specialized business systems—Laboratory Information Management Systems (LIMS), legacy ERP solutions, and proprietary accounting software—that were hard-coded to interact with Acrobat 4 or 5. These systems utilize "Watched Folders" (a Distiller feature where the software automatically converts any file dropped into a specific folder). legacy ERP solutions
Some vintage software sites like the Macintosh Repository or WinWorld host these for historical/emulation purposes, but they require original license keys to be used legally.