TypeError: argument of type 'NoneType' is not iterable

Hi Venkata! Thanks for your bug report. The bug you describe has been fixed in the branch I have linked and should be available in the next release. Please continue to report any bugs you may find in software-center. Thanks again for your help!

This bug was fixed in the package software-center - 2.1.16

---------------
software-center (2.1.16) maverick; urgency=low

  [ Gary Lasker ]
  * softwarecenter/view/purchasedialog.py:
    - make the "Terms of Service" popup display correctly in
      front of the purchase dialog (LP: #625398)
    - tweak the width of the purchase dialog window to
      accomodate the current Ubuntu SSO page width
  * softwarecenter/view/channelpane.py:
    - always default to hiding non-app packages when
      selecting a new channel item in the left navigation
      pane (LP: #630631)
  * softwarecenter/view/softwarepane.py,
    softwarecenter/view/availablepane.py,
    softwarecenter/view/channelpane.py
    softwarecenter/view/installedpane.py:
    - display a spinner while loading an applist view
      (LP: #630641)

  [ Michael Vogt ]
  * remove debug output
  * merged lp:~mmcg069/software-center/small-fix (many thanks!)
    - prevents the exposure of the carousel icons before they have
      been allocated.
  * verify sortmode when building categories (LP: #618411) and
    ignore categories with unknown/unsupported ones
  * merged lp:~mmcg069/software-center/cleanup-software-section-code
    that fixes LP: #624786 (many thanks)
  * make sure there is always a toplevel transaction for a pending
    purchase even if s-c waits for the for-pay repository to become
    available (LP: #627608)
  * softwarecenter/view/purchasedialog.py:
    - support both "failure_reason" and "failures" as error strings
      from the agent
  * merged lp:~mmcg069/software-center/Bug617443 (LP: #617443)
  * merged lp:~mmcg069/software-center/bug628714 (LP: #628714)
  * merged lp:~mmcg069/software-center/hover-highlight-tweaks to
    use correct prelight color

  [ Kiwinote ]
  * data/featured.menu.in:
    - fretsonfire instead of fretsonfire-game, due to desktop file changes
  * data/software-center.menu.in:
    - use correct icon for system category, thanks vish!
  * softwarecenter/apt/aptcache.py:
    - don't crash on broken dependencies (LP: #630579)
      (testcase: acl2-books)
  * softwarecenter/db/application.py:
    - set pkgname for deb files correctly (LP: #628787)
      (testcase: replace _ with - in filename of an outdated deb file of s-c)
  * softwarecenter/view/appdetailsview_gtk.py:
    - never display the description of a different pkg
      (testcase: browse to any appdetails view and then to fluendo dvd player)
    - don't crash if icon for 'where is it' is None (LP: #629845)
    - don't crash if icon for addon can not be opened (LP: #629937)
    - don't display add-ons when we have an error
      (testcase: deb file of wrong architecture)
  * softwarecenter/view/appview.py:
    - fix startup crash (LP: #618411)
  * softwarecenter/view/availablepane.py:
    - set section for subcategory view (this means that we now have a bg)
  * softwarecenter/view/installedpane.py:
    - don't return to installed overview list on reopening db
  * softwarecenter/view/widgets/pathbar_gtk_atk.py:
    - fix visual corruption on appending pathbar part
      (testcase: channelpane > details > different channelpane > details)
 -- Michael Vogt <email address hidden> Tue, 07 Sep ...