AttributeError: 'DebPackage' object has no attribute 'pkgName' when installing virtualbox deb in kpackagekit

Binary package hint: kpackagekit

I had to install both VirtualBox and Acrobat reader which come in isolated .deb files (I mean I didn't setup repos for them, just used the .debs downloaded from the sites with firefox).
Opening them from the desktop spawned kpackagekit installer correctly, but both failed with a pretty generic error. Launching manually from a shell, I got this:

papaf@lino:~$ kpackagekit Scrivania/virtualbox-2.2_2.2.2-46594_Ubuntu_jaunty_i386.deb
isFIle
papaf@lino:~$ New transaction with tid "/21_daedaaad_data"
KPackageKit(5463) KpkIcons::actionIcon: action unrecognised: 9
enumFromString ( State ) : converted "" to "" , enum value -1
KPackageKit(5463) KpkTransaction::errorCode: errorCode: 3 "Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/packagekit/daemonBackend.py", line 109, in run
    threading.Thread.run(self)
  File "/usr/lib/python2.6/threading.py", line 477, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/packagekit/aptDBUSBackend.py", line 168, in wrapper
    func(*args, **kwargs)
  File "/usr/lib/packagekit/aptDBUSBackend.py", line 1263, in doInstallFiles
    if not deb.checkDeb():
  File "/usr/lib/packagekit/debfile.py", line 365, in checkDeb
    if not self.checkConflicts():
  File "/usr/lib/packagekit/debfile.py", line 313, in checkConflicts
    if self._checkConflictsOrGroup(or_group):
  File "/usr/lib/packagekit/debfile.py", line 197, in _checkConflictsOrGroup
    if self.pkgName == pkg.name:
AttributeError: 'DebPackage' object has no attribute 'pkgName'
"
KPackageKit(5463) KpkTransaction::finished: Failed.
KPackageKit(5463) KpkTransaction::finished: Yep, we failed.
KPackageKit(5463) KpkInstallFiles::installFilesFinished: Finished.
removing transaction from pool : "/21_daedaaad_data"

Kubuntu version:
Description: Ubuntu 9.04
Release: 9.04

kpackagekit:
  Installato: 0.4-0ubuntu8
  Candidato: 0.4-0ubuntu8
  Tabella versione:
 *** 0.4-0ubuntu8 0
        500 http://it.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status