Error: There is no parent object while creating inetnum

Hi,

I'm having trouble generating some assignments:

Error while creating object through syncupdates API: - From-Host: 
62.128.1.62
- Date/Time: Fri Jan 11 15:36:54 2013

SUMMARY OF UPDATE:

Number of objects found:                   1
Number of objects processed successfully:  0
   Create:         0
   Modify:         0
   Delete:         0
   No Operation:   0
Number of objects processed with errors:   1
   Create:         1
   Modify:         0
   Delete:         0
   Syntax Errors:  0

DETAILED EXPLANATION:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following object(s) were found to have ERRORS:

---
Create FAILED: [inetnum] 62.128.31.128 - 62.128.31.131
***Error: Authorisation failed
***Info: Syntax check passed

inetnum:         62.128.31.128 - 62.128.31.131
netname:         testblubb2
country:         DE
descr:           noris network AG
admin-c:         ML1-TEST
tech-c:          ML1-TEST
status:          ASSIGNED PA
notify:          guardian at noris.net
mnt-by:          NORIS-MNT
source:          TEST
changed:         moritz.lenz at noris.de
***Warning: Date '20130111' added to changed: attribute 
'moritz.lenz at noris.de'

***Error: There is no parent object

***Info: Authorisation for  [inetnum] 62.128.31.128 - 62.128.31.131
          using mnt-by:
          authenticated by: NORIS-MNT

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The RIPE Database is subject to Terms and Conditions:
http://www.ripe.net/db/support/db-terms-conditions.pdf

For assistance or clarification please contact:
RIPE Database Administration <ripe-dbm at ripe.net>

Generated by RIPE WHOIS Update version 1.50.2 on WHOIS2
Handled sync update (TEST, LGC, 2013-01-11 15:36:54)
  at /home/mlenz/src/kunde/kunde/add/kunde_ipaddr line 339

I'm kinda guessing that the 'parent object' that the error message talks 
about is meant to be the allocation -- but that exists:

$ whois -h whois-test.ripe.net 62.128.31.128
% This is the RIPE Database query service.
% The objects are in RPSL format.
%
% The RIPE Database is subject to Terms and Conditions.
% See http://www.ripe.net/db/support/db-terms-conditions.pdf

% Information related to '62.128.0.0 - 62.128.31.255'

inetnum:        62.128.0.0 - 62.128.31.255
netname:        DE-NORIS-990421
descr:          noris network AG
org:            ORG-TT1-TEST
country:        DE
admin-c:        ML98-TEST
tech-c:         ML98-TEST
status:         ALLOCATED PA
mnt-by:         TEST-NCC-HM-MNT
mnt-lower:      NORIS-MNT
mnt-routes:     NORIS-MNT
source:         TEST
changed:        nobody at example.com 20130111

and has the correct mnt-lowerk afaict.

So, what's the problem here?

Cheers,
Moritz