Using the Nokia NbuExplorer, Noki or similar utilities for Nokia phones it should be quite possible to export the contacts from Nokia ARC backup files and save them in form of a vCard file (.vcf). Seems to be working just fine.
Convert Nokia backup archive to vCard contacts.
We found 2 software records in the database related to .arc to .vcf file format conversion.
Microsoft Windows software - convert arc to vcf on Windows
A small usefull program for exploring and extracting of files created with Nokia PC suite
Convert from arc file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned arc to vcf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A free explorer for Nokia NBU files