You really need to trim that code down to something much smaller that still demonstrates your problem.

Statement that does not work but should:

push @dfdata_out, (\%dfdata_row);
[download]

Well, you're expecting an array of hashrefs and that's exactly what your push should do (the parentheses are unnecessary, btw).

Are you sure %dfdata_row contains what you think it does? Data::Dumper can help you determine its contents easily.