ODBM also uses .dir and .pag extensions, so maybe that's what created the files. Also, if you can't bring up the keys, maybe they were serialized with MLDBM so try using that. If you're a database guy/gal, check out my as yet un-announced DBD::DBM, a DBI driver for all types of DBM and MLDBM files - it comes bundled in the latest DBI 1.42 distribution.
updateOoops, just noticed the solaris/linux thing - the data files are platform specific, so you'll almost certainly need to dump them on solaris and re-import them on linux.