I even installed kdenlive on openSUSE 12.2 from the Standard-Reopository. If I use Project -> Add file and select a .avi - File kdenlive says, that the file couldn’t be read. I’m sure, that this file worked with opensuse 11.4 with kdenlive under the same conditions.
To make sure that there isn’t a failure inside my upgraded 12.2 installation I prepared a virtual machine with an openSUSE 12.2 from scratch, installed kdenlive and all security updates - but the problem hadn’t gone.
Perhaps certain codecs aren’t supported? You might try using kdenlive and melt from the packman repository instead. You can add packman easily in yast by going to add repositories. Just choose it from the list of community repositories.
Try importing a known supported file such as ogg theora to see if it works.
I just added the Packman repositories and refreshed the packages melt and kdenlive. Thank you for that.