When creating a new job (free style or copy from existing project), when the configturation page appears a gray shadow keeps over it. If I try to save the job I get a 404 message. I'm not sure since when this is happening, the last time we created a job was about a month (Jul 23, 2013, aprox.) I'm attaching a file with the jenkins log, some screenshots and a pdf with the system info.

Regards.
(Sorry about my English)