You can try using Win32::File instead of File::Find, for starters. Otherwise, windows being windows, if you want to know what size IT thinks a directory is, might as well ask it:

$temp = `Dir $your_directory_here`;
if($temp =~ m/(\s+)(\d+)( File)(\S{3})(\s+)(\S+)( bytes)/i){
   print "$6 bytes\n";
}
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That's some ugly code. Works though, least in XP. YMMV, and it won't give you sizes on subdirectories. The regex is a bit more brittle than I'd like...It'd be cleaner if you ripped all the /'s and ,'s out of the directory output first. Then you'd probably be safe just doing:

...
   if($temp =~ m/(\s+)(\d+)( bytes)/i){
...
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