Perhaps you meant to code you solution like this:

#!/usr/bin/perl
use 5.016;
use warnings;

#  1055294
my $line = ' j1000010017 6790194100109201301092013THIS TO BE PRINTED  
+M PW09-3PY248005BIK00 ';
say substr( $line, 38, 20);
say substr( $line, 68, 3);

=head EXECUTION

C:\>D:\_wo\1055294.pl
THIS TO BE PRINTED
248

=cut
[download]

Explanation: perldoc -f substr.