This works fine:

package EDI::123;

sub here {
print "I am in ", __PACKAGE__, "\n";
}

package main;

EDI::123::here;
[download]

Top-level packages can't start with a digit. But the whole package name is EDI::867, so it doesn't start with a digit.

Also, creating an EDI directory and an 867.pm file in it, use EDI::867; worked fine.