[Plugin: NextGEN Gallery] Getting error message when trying to upload photos to a gallery

Have been trying for the past 24 hours to upload pics to a new NextGen photo gallery. But every pic I try to upload to the gallery I create comes up with an error message and the result is that no pics have been uploaded to the gallery at all. I’ve done this three times with no success, tried uploading the pics individually and I get error messages every time and this message that comes up at the end:

Directory /usr/local/www/data/wordpress-mu-2.6.1/wp-content/blogs.dir/92/files/thievery-corporation contains no pictures

I’ve uploaded several galleries with no problem before this, so I’m doing everything the same as before…