Errorcheck in line 87 should have $settree['rsp']['err'] instead of $top_level_tree...

The check for error returned in line 87 of flickr.module is wrong, I believe.

It is currently:
if (!empty($top_level_tree['rsp']['err']) || empty($settree))

but it should be
if (!empty($settree['rsp']['err']) || empty($settree))

This causes an error instead of the expected response if the API key is invalid.