This happens when the fixture tries to strike the lamp, but cannot.
First thing to try is to leave it off for about 5 minutes, disconnect DMX, and then try to strike it manually from the menu.
If this doesn't work, try a new lamp.
If it still doesn't work, then it it probably a bad ignitor.
HOWEVER, if you are seeing the LAMP OUT ERR, then you lamp has reached the end of it's usable life and needs to be replaced. You must also re-set the lamp life counter via the menu.