please detatch stdin, stdout and stderr from the terminal on backgrounding (-b)
not doing so will sometimes make the shell you used to start icecast with hang when you later want to exit it, and some xml-libs icecast uses often also suddenly spew errors right into the terminal.
a workaround I use sometimes is to start icecast with icecast2 -b -c blah 0>/dev/null 1>&0 2>&0 (bash redirections, and taken from memory, beware)