Not sure if what others have said has helped, but my take is that your here-me doc is wrong...

system("$ENV{'ORACLE_HOME'}/bin/rman <<EOF
             connect target /
             connect catalog aaaaaaaaa/bbbbbbbb@rman-live
             show retention policy ; 
             show all ;
             EOF"
)
[download]

should be

system("$ENV{'ORACLE_HOME'}/bin/rman <<EOF
             connect target /
             connect catalog aaaaaaaaa/bbbbbbbb@rman-live
             show retention policy ; 
             show all ;
EOF
");
[download]

see here-me doc search for <<EOF.

The indent of EOF is wrong, I think

Try running your system out to a file, via a unix cat command or equiv