Redmine

Redmine 1.2.1
Windows XP SP3

When I try to do a bulk update/edit (select all issues, right click, select Status, select Closed status), I get the following proxy error. This is regardless of how many issues I select, or whether I run off the local machine or a remote machine.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request POST /issues/bulk_edit.

Reason: Error reading from remote server

Apache/2.2.3 (CentOS) Server at XXXXX.YYYYY.com Port 80

Anyone have any pointers?
Thanks in advance.