Internal Server Error for 304 - not actually an error?

[GoogleCodeExporter]

[Thu Nov 04 14:29:39 2010] [notice] [1104/142939:INFO:net/instaweb/
apache/mod_instaweb.cc(319)] ModPagespeed Response headers:\nHTTP/1.1
304 Internal Server Error\r\nX-Powered-By: PHP/5.3.3-1ubuntu9.1\r
\nLast-Modified: Thu, 04 Nov 2010 16:22:38 GMT\r\nX-Mod-Pagespeed:
0.9.0.0-128\r\n\r\n

Like bug 25, we seem to be saying that a 304 response is Internal Server Error 
(at least in logs).

Looks like Jan just found the solution.

Original issue reported on code.google.com by sligocki@google.com on 5 Nov 2010 at 3:45