I got a used oster 4812 bread machine from a friend. Making my first batch of bread and it seems the paddle is struggling a bit and there are occasional "squeaks" as if the internal gears need a bit of lube. What do I do?

Your drive belt is slipping dear. You'll need to pull the bottom cover off and replace it. Belt are sold here: http://www.amazon.com/Sunbeam-056386-Oster-breadmaker-belt/dp/B000238A34

Also perform these services for best results:

Servicing Your Automatic Breadmaker

For best results perform the following services annually.

Warning: Use only Lock-Ease Graphited Lock Lubricant for the following services. Other lubricants tend to damage the seal and/or gum-up the drive shaft. To purchase your squeeze-bottle version of Lock-Ease Graphited Lock Lubricant go online or visit your local Ace Hardware or NAPA Auto Parts Store.

Lubricating the Pan Shaft with Lock-Ease:

Remove the bread pan insert and place it upside-down. Apply Lock-Ease to the top of the pan's coupler. Gently rock and rotate the coupler to allow for penetration. Repeat 3 times. Allow to air-dry 1 hour. Wipe away any remaining residue.

Lubricating the Wheel Shaft with Lock-Ease:

Access the electric motor/drive wheel platform. Check that the screws securing the electric motor to the platform are good and tight. Do not lube the electric motor.