A process has received a signal indicating that it attempted to execute an instruction that is not allowed by the kernel. This usually results from running programs compiled for a slightly different machine architecture. This message is usually accompanied by a core dump, except on read-only file systems.
If you are booting from a CD-ROM or from the net, check Readme files to make sure you are using an image appropriate for your machine architecture. Run df(1M) to make sure there is enough swap space on the system; too little swap space can cause this error. If you recently upgraded your CPU to a new architecture, replace your operating system with one that supports the new architecture (an operating system upgrade might be required).
Sometimes this condition results from a programming error, such as when a program attempts to execute data as instructions. This condition can also indicate device file corruption on your system.