Auto Blog Errors - WP HTTP Error: cURL error 28

I'm not sure when this started but last week I noticed that several RSS feeds stopped processing via the WPMU Auto Blog plugin on our website. Every time the feed service tries to process, we get this error:

WP HTTP Error: cURL error 28: Operation timed out after 10001 milliseconds with 816 out of 14633 bytes received

The errors change only slightly. Here is another example:
WP HTTP Error: cURL error 28: Operation timed out after 10000 milliseconds with 2852 out of 14633 bytes received

We tried to do some research and found that it may have to do with XML-RPC, so we disabled the "Disable XML-RPC Pingback" plugin, that we had active, and tested. Same result.

We tired disabling all of the plugins and switching the default theme -- same result.

We also asked our hosting company, Rackspace, to raise the execution limit for PHP to 120 seconds. Still not working.

At this point Rackspace wanted to know what curl command the WPMU Auto Blog uses. Can you help me troubleshoot this and/or provide that information? I have enabled WPMU DEV Support for this site if you'd like to take a look.