The TypeError should be fixed by this commit:
https://git.fedorahosted.org/cgit/koji/commit/?id=9103bda257e235b26bdbeb9198299cbc13a0d515

Then there will be an Unexpected EOF error as described here:
https://lists.fedoraproject.org/pipermail/buildsys/2015-January/004484.html

relevant debugging output:
{{{

/usr/lib/python2.7/site-packages/koji/init.py(1945)callMethod()
-> if isinstance(e, OpenSSL.SSL.Error):
(Pdb) e
SysCallError(-1, 'Unexpected EOF')
(Pdb) n
/usr/lib/python2.7/site-packages/koji/init.py(1946)_callMethod()
-> for arg in e.args:
(Pdb) e
SysCallError(-1, 'Unexpected EOF')
(Pdb) e.args
(-1, 'Unexpected EOF')
(Pdb) n
/usr/lib/python2.7/site-packages/koji/init.py(1947)_callMethod()
-> for , , ssl_reason in arg:
(Pdb) n
TypeError: "'int' object is not iterable"
/usr/lib/python2.7/site-packages/koji/init.py(1947)_callMethod()
-> for , _, ssl_reason in arg:
(Pdb)
}}}

This should all be working now

still broken on the rawhide composer:
https://lists.fedoraproject.org/pipermail/releng-cron/2015-October/010330.html
{{{
2015-10-14 05:15:29,444: ERROR: ['block-pkg', 'dist-5E-epel', u'covered'] stdout: "TypeError: 'int' object is not iterable\n" stderr: ''
2015-10-14 05:15:29,444: ERROR: ['unblock-pkg', 'dist-5E-epel-build', u'covered'] stdout: 'GenericError: package covered NOT blocked in tag dist-5E-epel-build\n' stderr: ''
2015-10-14 05:15:41,848: INFO: Blocked covered on el5
2015-10-14 05:15:41,848: ERROR: ['block-pkg', 'dist-5E-epel', u'covered'] stdout: "TypeError: 'int' object is not iterable\n" stderr: ''
2015-10-14 05:15:41,848: ERROR: ['unblock-pkg', 'dist-5E-epel-build', u'covered'] stdout: 'GenericError: package covered NOT blocked in tag dist-5E-epel-build\n' stderr: ''
2015-10-14 05:16:23,804: ERROR: ['block-pkg', 'f23', u'mate-applet-lockkeys', u'apache-scout', u'nodejs-grunt-contrib-copy', u'pig', u'pure-glpk', u'CableSwig', u'python-rfc6266', u'pyjigdo', u'vfrnav', u'pure', u'oat', u'oozie', u'mate-themes-extras', u'python-ufc', u'netbeans-platform', u'hbase', u'rubygem-celluloid', u'spark'] stdout: "TypeError: 'int' object is not iterable\n" stderr: ''
2015-10-14 05:16:38,553: INFO: Blocked mate-applet-lockkeys on f23
2015-10-14 05:16:38,554: ERROR: ['block-pkg', 'f23', u'mate-applet-lockkeys'] stdout: "TypeError: 'int' object is not iterable\n" stderr: ''
[...]
}}}