The "Shockwave Flash" plugin you see
is the flash-plugin-10.0.32.18 plugin. Yes, I know is says "Shockwave Flash" and not "Adobe Flash", which can be somewhat mis-leading. Here is a screenshot of flash-plugin-10.0.32.18-release.i386 installed with FF v 3.5.3 as seen in
Notice the filename. libflashplayer.so
Uninstall those swfdec* packages.