I am writing a module that looks like this:

package foo;
require Exporter;
@ISA = qw(Exporter);
use CGI qw(header);
@EXPORT = qw(header);
1;
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And then in another file:

use foo;
print header();
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This worked before I installed perl 5.6.0. Now it tells me that &main::header is undefined. I have tryed rewriting the module in various different ways. Why doesn't this work?