I just clicked the .deb link in your earlier post from Firefox browser on my N900, chose 'Open', then it downloaded and the App Manager took care of the installation. To launch, I click the Instinctiv icon I've added to one of my desktops. It launches perfectly, every time.

Minor niggle. I'm not sure if it's my desktop theme, but I find it quite hard to read the numbers of tracks against each album. Mine is showing up light blue against a not so light blue background and the contrast is very low, making it hard to read. The track times are dark grey and easy to read.