scaled images created in wrong directory

I have an imagecache preset that scales images to within 250x250. I am using that preset in a view I created to display the image fields of a content type I've created. The view works correctly when I do not use the imagecache preset.

When the preset is selected as a field option for the images and the page is loaded, the image files do not exist. This is the path of one of the images:

http://example.com/main/sites/example.com.main/files/imagecache/gallery/...

Files are created in /usr/local/www/drupal-5.3/sites/example.com.main/files with names like this:
gallery01-imagefilename.jpg

On subsequent page views, more files are created, with _0.jpg, _1.jpg, etc after "imagefilename".

There is a string of directories related to imagecache within example.com.main/files :
imagecache/gallery/sites/rondenitto.com.main/files/paintings/
Each of these directories is empty, however. I have changed the ownership of each directory in this chain to 777, but there is no change in behavior.

Is the double slash in the http address of each image indicative of a problem?
Why might imagecache be writing files to /files, but not the subdirectories of /files that it created?