That's weird. I had it on my Galaxy S II (with the newest software update which came out two weeks ago) and now I have it on my Galaxy S Blaze, both work just fine without root, and both have the Tethering Manager service running.
The Blaze is especially impressive, it was pulling 6-10mb down in an area where my S II usually gets 3-7. I was having trouble with my home router so I pulled out my Blaze and tethered to it for fifteen minutes to download some updates to my computer.
Castrol EDGE 5W-30 is my drug of choice.
Toyota | moving forward
Primary: iPhone 5 (AWS), Lumia 521, and Exhilarate HSPA+/LTE (T-Zones line): 5 lines, 1x $15 4.5GB data, 3x $2.99 T-Zones (truly unlimited 4G data), myFaves, corp discount + $10/mo loyalty discount = $94/mo tax inclusive
Secondary: iPhone 3GS: Airvoice Wireless, Samsung Fascinate & HTC Trophy: Page Plus