I have found only one place on the 'net where I could possibly *buy* an old copy of office 4.2.1 for mac.
Unfortunately, the email address is encrypted by a silly javascript which refuses to work in all the browsers I tried (microb, firefox, konqueror). Maybe it works in internet explorer and somebody can look at the following page and let me know the mail address?

http://www.dans20thcenturyabandonware.com/contact.html

Ah, and I admit I searched also in p2p and ehr... sites, but with no joy