category drop-down not showing categories

So, I’m trying to put a category drop-down list on my sidebar that will give me just a drop-down showing all my categories, and if it could do my sub-categories that’d be great to. I’m using this code, from a page on the Codex:

<form action=”<?php echo $PHP_SELF ?>” method=”get”>
<?php dropdown_cats(); ?>
<input type=”submit” name=”submit” value=”read” />
</form>

It used to work on my old blog on my old host but it now only shows the “uncategorized” category though I have 4 categories and 4 sub-categories. Could someone please give some suggestions on what to do that might whip it into shape?