In general, it means something it spitting out output (on STDIN or STDOUT) before your print your headers. Simply try to run this script on the command line and you will see that it produces this error: 
Undefined subroutine &main::param called at /tmp/blah line 9.

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Check the CGI man page for details, but doing use CGI qw/:standard/; should resolve it.

In reply to Re: simple cgi script error by davidrw
in thread [untitled node, ID 460085] by Angharad

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