Four things stand out:

1. The path separator will need to change: @path=split(/:/,$ARGV[$m]
2. Why does the definition of "text" exclude 'I'?

   # does it contain text?
   if ($i =~ /A-HJ-Za-z/)
   [download]

3. You'll probably need to set up a short cut using wperl.exe if you want to:

   print STDERR "Just drag your datafiles in turn onto the program icon,\
   +n";
   [download]

4. You might want to wrap the main body in a loop over @ARGV, to cater for multi-file drag&drop.