Are you using
use strict;
use warnings;
in your code?
How exactly does this help the OP? The code provided does not have problems when strict and warnings are added.
As your error message says, the script could not find the files.
The OP knows that:
This is the problem I encounted ,and the following is the code where the above missing files are used
And the gem:
give the absolute path to the file names
Of course that will help with:
there are many commands used in the program, like "perl5 " and the two files names follows with the "sort"command ,I just can't get the meaning from these.