apache 2.2 - Ubuntu 10.04 + Lighttpd. can't bind to port: :: 80 Address already in use

I've had a machine running Ubuntu 9.10, with lighttpd and PHP.
After the OS update to Ubuntu 10.04, it installed apache2 automatically for some reason (I believe it is due to some dependencies php -> apache). Anyway I removed apache2 permanently, but starting lighttpd fails, giving provided error -

can't bind to port: :: 80 Address already in use

using

sudo lsof -i :80

results in empty list!!

What is wrong?!

thanks in advance,
m.

Answer

Are you running lighttpd as root (sudo)? Normal users can't launch processes that bind on ports < 1024 ...