Unless someone here happens to know the tool you are using - from your previous posts I assume it's "Checkmarx" - we're not going to be able to explain it to you any better than the documentation of the tool, so I recommend you look there.

open ( UNFILE, "<", "$file" ) || print ( "Cannot open file $file\n" );

Your code will continue running even if the open fails. I already linked you to "open" Best Practices.

$item_desc{$item_idx} = "$tmp_index.$temp_str\n$temp_desc";

What are $item_idx and $tmp_index? It's their only use in this code. I hope this code uses strict and warnings... see also Short, Self-Contained, Correct Example and How do I post a question effectively?

The better your questions, the faster you'll get good answers.