I'd term this a workaround, as it gets the current package installed while we wait for a fix.
My preferred solution is to install the current package (which installs r48), instead of these ad-hoc work arounds (that install r115) which may have problems when the package is fixed.
(For instance, r48 is reported to work better than r115, and we know r115 doesn't work at all in Konqueror, so installing r48 is the only thing that will work for Konqueror users. I think we should vet 115 very carefully before committing to it.)
The problem is, the current package downloads r115, which is not what we want, because it is expecting r48. Luckily, the current package has a provision for you to download the r48 version yourself and tell the installer where it is. Adobe has a zip file of all Flash 9 players they've released that you can get the r48 version from (they keep it available for developers to test their flash projects against).
You won't be able to enter the location of the r48 version by default, because Ubuntu's debconf is set to only show questions of priority 'high' or above, and the question about the location of r48 is priority medium. You have to reconfigure debconf to show questions of priority 'medium' first (afterwards you can reset it to 'high'). This is explained below.
The steps I followed were:
I got the Flash 9 archive from here: http://fpdownload.macromedia.com/get/flashplayer/installers/archive/fp9_archive.zip
which I found on this page: http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_14266
Unzip the .zip file (use unzip from the command line or file-roller)
Copy the r48 version to /tmp and change it's name to what the installer is expecting at the same time:
cp fp9_archive/9r48/install_flash_player_9r48_linux.tar.gz /tmp/install_flash_player_9_linux.tar.gz
reconfigure debconf to show medium priority questions:
sudo dpkg-reconfigure debconf
It will ask 2 questions. The answer to the first should be 'Dialog' (Ubuntu's default). The answer to the second question about priority of questions to show should be 'medium'. (Low also works)
You can use apt-get, synaptic or aptitude.
apt-get (command line)
sudo apt-get install flashplugin-nonfree
synaptic - search for flashplugin-nonfree and install it.
aptitude - you probably know how to select a package for installed if you use aptitude.
For any of the methods, debconf should ask you what the location of the downloaded file is. Enter /tmp (Do not enter the filename of the file, just the directory location) and it should install correctly.
If you want, reconfigure debconf to only show you 'high' priority questions again:
sudo dpkg-reconfigure debconf
I believe downloading the .zip from adobe in the installer is one of the solutions being looked at to fix this bug, but the downside is that the 65M size is quite large for dial-up customers. Not sure what the maintainers solution will be, but this will at least get the current one installed if you can afford the 65M download.