From Jay Rogers:
Some versions of the perl debugger itself need to be patched to work with emacs. They are perl versions 5.001 and less, and version 5.004_01. To fix, locate and change the code similar to the following code in lib/perl5db.pl
if (-e "/dev/tty") {
$console = "/dev/tty";
$rcfile=".perldb";
}
elsif (-e "con") {
$console = ""; <---- change "con" to ""
$rcfile="perldb.ini";
}
else {
$console = "sys\$command";
$rcfile="perldb.ini";
}
Doug Campbell also has some suggestions for improving the interaction of perldb and Emacs.