[Plugin: WP Super Cache] supercache breaking xml-rpc somehow

I upgraded to 0.9.3 yesterday and one of the XML-RPC calls began failing. I’m posting via XML-RPC. The actual post call works, but the “publish” call results in an error. Digging into the Python XML-RPC library, here’s what I found the server was returning:

<br />
<b>Warning</b>:  opendir(/home/nickarne/public_html/tweetsnet/wp-content/cache/meta/) [<a href='function.opendir'>function.opendir</a>]: failed to open dir: No such file or directory in <b>/home/nickarne/public_html/tweetsnet/wp-content/plugins/wp-super-cache/wp-cache-phase2.php</b> on line <b>632</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/nickarne/public_html/tweetsnet/wp-content/plugins/wp-super-cache/wp-cache-phase2.php:632) in <b>/home/nickarne/public_html/tweetsnet/wp-includes/class-IXR.php</b> on line <b>387</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/nickarne/public_html/tweetsnet/wp-content/plugins/wp-super-cache/wp-cache-phase2.php:632) in <b>/home/nickarne/public_html/tweetsnet/wp-includes/class-IXR.php</b> on line <b>388</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/nickarne

Changing supercache to “half-on” seems to have solved the problem.

It appears to me that the Python library was unable to parse that error message… it throws “ParseError: junk after document element: line 2, column 0”. I’m not sure what’s going on here… is supercache not playing well with XML-RPC?