If your code is being run in the same directory as the files you could always do something like this:

while (<*txt>) {
    # process the file ($_ will contain the name of the file)
}
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This would remove the need for the "qcode" file, since it's only doing what the file system already does---namely, maintain a list of file names.

As for the rest of the code: I think you're missing some braces in various places. If you tried to run your code through a good indenting text editor, you would notice that things are not lining up as you would expect. Also, doing a perl -cw ./yourprogram.pl says there are syntax errors with your script.

Finally, I'm not sure why you're processing the file twice. I'm assuming there is a good reason, but it's not apparent to me at the moment.