For what it’s worth, I’m seeing exactly the same thing and have a similar posting (just saw yours). One interesting thing: if you create a post and upload a file at the same time, it works. Thereafter, if you go to the media tab and try to upload something it works. It’s only that first use on a new blog.
If I click on the Media button in the sidebar menu of your admin panel I get the same error – however, if I click on the drop-down first and then on “Add New” – then it works.
You need to install the fastcgi patch for IIS7/7.5 or the work around. You can get it from iis.net
I installed the 3.0 v and I got similar problem. But I can’t upload any file. It says “has failed to upload due to an error
Unable to create directory /blog/wp-content/uploads/2010/07. Is its “parent directory writable by the server?” or /blog/wp-admin/upload.php” The page cannot be found, but it’s there (ftp). And when I try to change the folder permission to 777 on wp-content it says 00 ‘SITE CHMOD 777 uploads’: command not understood. I don’t know what to do.
One you uploaded a file upload.php don’t throw this error. I think it is a bug reading the folder for images. SInce there are none, a 404 error is thrown.
