I installed "easymp3gain-qt 0.5.0+svn135-6" from the Ubuntu Software Center and... it does nothing!
I mean: the main program interface is opened, but... when I ask it the expected action (to normalize the volume of some mp3 audio file), the program stops and asks me: "Is mp3gain installed?"
I tried to install mp3gain, but it is only to Windows and it doesn't run with Wine!
So... How can I use this?