Ubuntu – Error: “Fixing recursive fault, but reboot is needed” need to put acpi off


I having trouble with a Acer Aspire 2010. Whenever I boot, just one moment after grub I get the error "Fixing recursive fault, but reboot is needed". So I searched for it, and I found this workaround: adding acpi=off to grub. Now it does boot, but I can't power off well. I always need to perform a hard-reset. The computer is running Lubuntu 12.04 (couldn't install normal ubuntu due to pae). Strange is that the live installer runs without problems. Also, removing the battery, disconnecting AC, etc… doesn't help.