my @a = read_file($outputfile1)
     or die "couldn't read $outputfile1 - $!";
# ........................................^^

##</code><code>##

couldn't read C:\log_parsing\app_output.txt - No such file or directory at log_windows_new.pl line 444.
#.............................................^^^^^^^^^^^^^^^^^^^^^^^^^

##</code><code>##

     my @a = read_file($outputfile1)
     or die "couldn't read $outputfile1 - $! [$^E]";