when $recursive is used on a windows machine, the "windows compatibility" hack in check_dir_exists fails.

eg when:
$CFG->dataroot = "c:\mysite\moodledata"
make this dir = "c:\mysite\moodledata\test\1"

this call:
$dir = str_replace('
', '/', $dir); //windows compatibility

makes $dir contain the "make this dir" but with \ turned into /

then this call:
$dir = str_replace($CFG->dataroot . '/', '', $dir);

fails under windows. - as $dir doesn't match what is contained in $CFG->dataroot - eg it looks like this:
$dir = str_replace(c:\mysite\moodledata/, '', c:/mysite/moodledata/test/1)

it should be replaced to something like this:
$dir = str_replace(str_replace('
', '/', $CFG->dataroot) . '/', '', $dir);

(thanks to Colin from OU for help finding the bug!)

Dan