Installing pecl fileinfo on windows..

Currently trying to install php_fileinfo.dll for version 5.0.5 on
windows:

http://pecl4win.php.net/ext.php/php_fileinfo.dll

I've copied this into c:\php\ext\php_fileinfo.dll, and included the
following in php.ini: extension=php_fileinfo.dll (I initially tried
'pear install fileinfo' but it was yielding a dsp error). I've been
trying to execute the following code:

if(is_file($item)) {
$info = finfo_open(FILEINFO_MIME);
echo finfo_file($info, $item) . "\n";
finfo_close($info);

}

I'm getting the following errors/warnings:

Warning: finfo_open(): Failed to load magic database at '(null)'.
Warning: finfo_file(): supplied argument is not a valid file_info
resource..

I've checked that c:\php\extras\magic.mime exists, too; but the
documentation I've found implies I woudn't need to indicate this
explicitly in php.ini because it's the default location (I've certainly
tried it with that, though, too).

I'm not certain what else I ought to do/configure, etc. Thank you for
any input..