Having problems uploading files?

You've uploaded Drupal version 7.0 fresh out of the box. Having played around a bit with the new administration interface, it is time to create some content. So you write your first Article, the new content type that replaces D6' Story. It comes with an option to upload a picture, which will sit in the upper right corner of the page with your article text auto-wrapping around it. Nice! Just choose file. Click Upload... Warning: move_uploaded_file() [function.move-uploaded-file]: Unable to access public://my_pic.png in file_save_upload() (line 1528 of ..../includes/file.inc). Ouch! I was amazed I had to patch core to make the uploading of files possible on a hosted server. It's a simple change in one line, but you would have thought that such an obvious error in a basic operation was spotted before the official launch... I guess every system has its teething problems... Edit: this bug was fixed in Drupal core 7.8.