I've recently installed Mint 13 KDE and now when clicking on a programs 'install' button in the software manager, the button disappears but nothing is downloaded/installed.
UPDATE: I just used the update manager for the OS and it warned me that I had 2 broken packages. Could that be why no other software will install?
Mint itself updated okay, though.
2nd update: I don't know how, but I decided to try the software manager and it functioned as it should for an hour or so while I installed a few programs, though it did hang/crash on me at the end. I experienced this same crash with Mint 12 kde some time ago.