Lost manual I believe the model is DH90 U, it's about 9 years old

Ice buildup is most often caused by low freon. Is the unit 10 years old or more? Might need a recharge. Turn it off and let it thaw then back on. If it ices up again, it likely needs a recharge.

also at
WHIRLPOOL DEHUMIDIFIER Parts Model ad75ust0 Sears PartsDirect

Here is a link to an Owner's Manual for a Haier 45 pint dehumidifier. Not sure if yours exactly like it or not, as you didn't mention a model number. You can download and print the manual for future reference.

http://www.haieramerica.com/cool-heat-air-quality/dehumidifiers/45-pint-capacity-electronic-control-115-volt-dehumidifier-de45ek-7

Look for the download in the left hand lower left on the page.

Hope this helps and thanks for choosing FixYa.

Your model Kenmore Dehumidifier, I believe was was made my Haier, for Sears under the Kenmore name. In which case "01" indicates a circuit failure shutdown and needs to be repaired by an authorized Sears service technician. As it may still be in warranty.

Hope this helped you and thanks for choosing FixYa.

Here is a link to what I believe is the Manual for your unit. It covers several model numbers.
You can download and print the manual if you like.

http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000074758.pdf

Hope this helps you get up and running. Please let me know.

What you have there is a humidifier, not a dehumidifier.

You will need to put an amp meter on the compressor wires and monitor the reading till it trips the breaker. If the reading exceeds the name plate spec then chances are the compressor is going bad.If the spec is in watts, take your amp reading and multiply it by 120 volts this will give you the wattage of the compressor. For a second opinion take it to repairshop to see if it is worth repairing.
Good Luck!

THE DRAIN LINE IS CLOGGED TAKE OFF THE HOSE FROM THE UNIT AND BLOW AIR BACK THRU THE UNIT,, IT IS NOT UNDER A PUMP SYSTEM IT IS GRAVITY, IF IT WON'T DRAIN IT'S CLOGGED

It may have lost its charge of refrigerant. Check the warranty for sealed system, or if it is just the compressor which is covered. There are coils above the bucket area. Check for possible frost on only part of the coil. It is a sign that it has a leak at some point and has lost its refrigerant charge. If it lost all the gas there will be no frost nor condensation on the coils. Four years old and $75 bucks, its your choice.

Make sure the buicket is seated all the way. Sometimes it doesnt fully engage on the left side. If it is then it may need to be serviced. LG has a 5 year warranty on these models. They usually will tell you of a service center nearby which will service it free of charge since it is under warranty. If you do not live near a service center they may ship you a replacement and you send your old dehumidifier back to them. Make sure you have your reciept when you contact them so they can verify it is under 5 years old.