Had several 0.4.1 instances on a Redhat box, and had to
migrate them to a FreeBSD box.  I get this error when
trying to open db/nodes.user in dbhash.py:

error: (79, 'Inappropriate file type or format')

On both machines, anydbm says it is using dbhash by
default.

Thinking maybe this was something fixed in a newer
version, I upgraded to 0.6.0b3, and followed the
upgrade instructions, and get the same
end result on the attempt to open this file.

Both machines are Intel architecture.  Is there a
chance the DBM files are incompatible or something?

Logged In: YES 
user_id=6405

DBM files sometimes don't like being copied around. *shrug* as 
to what's going on. 

Your best bet is to export the data to CSV and import it at the 
other end.