SVN2BZR: what is svn.dump?

[Alexander Belchenko]

I try to convert some svn repositories to bzr one with svn2bzr tool:
http://bazaar.canonical.com/svn2bzr

But I'm stuck with problem. This utility want to read "dump file with
the history of a given Subversion repository". What it means? How to
create this "dump"? It's definetely not SVN repositary itself because
script want to read plain file:

D:\user\MyCode\CVS2SVN2BZR>svn2bzr.py SVN_repo BZR_repo
Traceback (most recent call last):
   File "D:\user\MyCode\CVS2SVN2BZR\svn2bzr.py", line 971, in ?
     main()
   File "D:\user\MyCode\CVS2SVN2BZR\svn2bzr.py", line 960, in main
     dump_file = open(dump_filename)
IOError: [Errno 13] Permission denied: 'SVN_repo'

Actually I want to convert my old CVS branches to BZR, but Tailor is
very unclear and too complicated tool, and I want to try toolchain
cvs2svn->svn2bzr first. Converting to svn is really simple with cvs2svn.

Please, give me the hint.

--
Alexander