Frost on evaporator coils

I recently purchased a Cavalier USS-8-64 and last night when I opened it up, I noticed that there was frost on the evaporator coils.

Is this normal?  If not, what are your suggestions?

Thanks for everyone's help.  This board has been a GREAT resource for me.

[johnieG]

Some frosting can be normal when you first fire it up, (empty cabinet, humid air)  but if it seems to stay frosted check for proper air flow (fan) over the coils & make sure the thermostat is cycling the compressor off or maybe a leaking door gasket ( you'd notice the fan making whirring sound around the door & it would leak cold air too) push in/around on it and compare noise level.

check your air flow like johnieG said and and the inner door flap is it closing all the way or is it their  '> if all is ok you have a low charge in the compressor and it would be best to shut it down and have it ckecked for leaks and recharged
good luck