maemo.org - Talk - default (alpha?) theme backgrounds broken after upgrade to cssu

I just upgraded my N900 from PR1.3 (.1, I think) to CSSU/Stable (6), and somewhere along the way it broke my default (alpha, I believe its called - the watery one on black background) theme backgrounds.

In settings>Themes pop-up, I still see it listed, and the thumbnail image alongside the name is there, and I haven't noticed any other broken info. If I try switching to another theme, that works; then back to alpha doesn't quite work properly and takes a long time whirring away, and I still don't have backgrounds.

The files under /usr/share/themes/alpha (and others) still appear to be there and the /etc/hildon/theme symlink still points at it.

My N900 software was a little broken before - h-a-m would fail to start or to view catalogues so all my updates were via FasterApp Manager, or, actually, via apt-get (I'm a Linux geek with admin skills but don't understand hildon much). There seem to be several repo's now, and I'm not sure which are currently active/up-to-date for stuff - are they all repository.maemo.org now? Its not got one with a hildon-theme-alpha I can install. The old original downloads.maemo.nokia.com seems to be not working since a long time ago. I hadn't known that was their decision not my issue, so only discovered there are replacement alternatives these last few days.

So what else is likely to cause this, and if its corrupted file (I had old old BackupMenu on and newer one since upgrade), whcih repo's should be added/enabled to reinstall it???

Thanks in advance?