I'm also experiencing this issue. Reinstalling/clearing cache didn't work for me, either. I also will crash ocassionally when searching for a song and adding a track to a playlist directly from the search results. I crash more often deleting tracks, however. I'm on Windows 7 x64, and this problem is consistant enough that it's extremely frustrating.
My boyfriend and I are having same issue. Knocks you off when you add song to playlist. Started 9/12/13 and still happening. When you get back on Spotify it paused the song where it kicked off and did not add to playlist.
Re: Spotify Crashes when Adding music to Playlist from Radio