You are using chdir from within a thread. I would avoid that, since it is never clear between operating systems, whether the "current directory" is per-thread or global per program.

Also, replace

system "mkdir $branchdir";
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with mkdir:

mkdir $branchdir;
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Also, output the filename and path in your error message. I already suggested that to you but you ignore it. Please explain why you ignore my advice.

I din;t ignored i posted same in earlier meesage Thread 1 terminated abnormally: threadccod_new.pl: open /home/sbi/Desktop/SRA/CCOD_TEST: fileneme is Z_CCOD_00327.txt$! at threadccod_new.pl line 77.

Remove the chdir line in your code.

Also, use absolute directory and filenames in all your code, especially for $branchfile.