I tried migration from 0.3.0 to the current cvs version.
I used the classic template and never edited dbinit.py,
so I simply copied roundup/templates/classic/dbinit.py
to a copy of the 0.3.0 instance.

Now the following problem occurs:

ratbert:/Projects/psp/roundup/cvs
$ PYTHONPATH=. ./roundup-admin -i ../unstable/tool-issues list user
Traceback (most recent call last):
  File "./roundup-admin", line 30, in ?
    sys.exit(tool.main())
  File "roundup/admin.py", line 987, in main
    ret = self.run_command(args)
  File "roundup/admin.py", line 912, in run_command
    self.db = instance.open('admin')
AttributeError: '_roundup_instance_1' module has no attribute 'open'

As soon as I uncomment the new lines in 
IssueClass, then it works again:

class IssueClass(roundupdb.IssueClass):
    ''' issues need the email information
    '''
#    INSTANCE_NAME = instance_config.INSTANCE_NAME
    ISSUE_TRACKER_WEB = instance_config.ISSUE_TRACKER_WEB
    ISSUE_TRACKER_EMAIL = instance_config.ISSUE_TRACKER_EMAIL
    ADMIN_EMAIL = instance_config.ADMIN_EMAIL
    MAILHOST = instance_config.MAILHOST
    MESSAGES_TO_AUTHOR = instance_config.MESSAGES_TO_AUTHOR
#    EMAIL_SIGNATURE_POSITION = instance_config.EMAIL_SIGNATURE_POSITION

Enabling either of the two lines causes the failure.

I have a localconfig with

EMAIL_SIGNATURE_POSITION = 'bottom'
INSTANCE_NAME = 'tool-issues'

but this doesn't seem to affect the problem,
I can remove these settings and with the lines
above enabled still get the same error.