3.5.1 on IIS7.5 unable to update plugins and themes

First off, here’s what I’m working with.

• a fresh installation of WP 3.5.1
• IIS7.5
• Windows 7 64-bit Pro

When I tried to upload a plugin in a zip file, I got the following error:

Missing a temporary folder.

When I tried to install a different plugin from a search, I got the following error:

Downloading install package from http://downloads.wordpress.org/plugin/add-cloned-sites-for-wpmu-batch.zip…
Warning: touch(): Utime failed: No such file or directory in E:\Sandbox\wordpress\news\site\news\wordpress\wp-admin\includes\file.php on line 179

Unpacking the package…

The package could not be installed. PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file ‘C:\Windows\TEMP/add-cloned-sites-for-wpmu-batch.tmp’

When I tried to install a new theme from a search, I got the following error:

Downloading install package from http://wordpress.org/extend/themes/download/custom-community.1.14.zip…
Warning: touch(): Utime failed: No such file or directory in E:\Sandbox\wordpress\news\site\news\wordpress\wp-admin\includes\file.php on line 179

Unpacking the package…

The package could not be installed. PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file ‘C:\Windows\TEMP/custom-community.tmp’

I found this forum thread 3.5 on IIS7 unable to update plug-ins and themes. The OP seemed to have the same issue as me, but the last post said that this issue was fixed in 3.5.1 and that a new thread should be opened. So here’s the thread. It’s not resolved. However, the work around suggested in the above thread still works.

Steps taken:

1. I modified wp-admin/includes/file.php to echo $filename in wp_tempnam(). The temp path was to the system temp directory. I DO NOT want to open up that directory to IIS_IUSRS, as was suggested in the above thread.
2. I set the upload_tmp_dir in php.ini to an existing dir. This had no effect.
3. I added the following to wp_config.php: define( 'WP_TEMP_DIR', ABSPATH . 'wp-content/' );. This resolved the issue.