If you look at the relay near the resistor, it looks like the armature has slipped out of place. This happens if there is a really hard drop on the amplifier. What happens is the G-force of the sudden stop overpowers the relay spring, and unseats the armature. This picture seems to show the armature as not seated flat in the relay frame: http://i254.photobucket.com/albums/hh88/funbiz99/al572%20eham/P1040135.jpg
That could be an illusion, but it looks skewed.
Further along that line, it looks like the physical hit was hard enough the transformer under the tubes hit the chassis and chipped. I can see a definite chip in the core right where it would hit the chassis, and other signs of a pretty hard drop. (Actually the drop doesn't matter, the stop does.)
UNPLUG the amplifier, be SURE you unplug it, and you should be able to grab the relay armature and slip it back into place.
I would also IMMEDIATELY call the shipper and say it appears to have concealed damage, and be sure to save the boxes. I would carefully and closely inspect the amplifier for bent metal, like the chassis below the transformer where the G-force of the transformer might bend the steel bottom.
What shape are the boxes in, and where was it shipped from? You can tell a hard drop by the cardboard being crushed either inside or outside.
It should have been double boxed with foam supports on the amplifier. Were the inner foam cushions in place? Look at the packing closely.