Can't inline calendar for some reason

Can anyone tell a newbie why this doesn’t produce output in an Apache
2.2 cgi script?

/usr/bin/calendar.each do |a| print a end

I have nearly identical code that DOES work above and below this line,
both, including date, cal, uptime and /usr/games/fortune.

FWIW, this was WORKING code until I upgraded to Ubuntu Lucid, &/or
Firefox 3.6.8, &/or Apache 2.2 in the Lucid distribution.