It seems there is a problem within Mozilla that in combination with the Apache web server can cause the response content to get mixed up with the headers. This is especially true for repeated requests: the first one might be fine, successive ones will show this bug. AFAIK the mozilla bugs are aware of some similar sort of behaviour but no fix has been committed and i can reproduce with any firefox in combination with our Apache/2.2.3 (Red Hat, built: Nov 12 2008 07:09:27). The attached fix finds the enclosing quote pair and removes anything outside it, which fixes the parse errors. Needs to be tested and forward ported..