...
(On Debian, don't install an older "-dev" package, like "libdb2-dev", as it'll override the newer stuff. You just need "libdb2" and "libdb2-utils", or "libdb4.3" and "db4.3-util", or similar.)
If all else fails, just convert the entire DB to text using this tool: http://spamassassin.taint.org/devel/db-to-text.pl.txt , and it's "-o" switch, and convert from text into the DB_File DB format on the other side using the same tool and the "-i" switch.
...