Since these appear to be in a tree, you might want to investigate File::Find, which works recursively. You can use the callback to the find() to move the files found to wherever.

find (\&checkfor, "D:/DOWNLOAD/DISTRBTN/I01/");
sub checkfor {
    if (-f $_) { print $File::Find::name."\n" };
}
[download]

That will print out the full pathnames of all files in DISTRVTN/IO1 and all of it's subdirectories.