nothing but invalid solutions, Diablo OS X mining

Code:

Starting DiabloMiner (GPU)...
-----------------------------
[4/25/12 4:32:52 PM] Started
[4/25/12 4:32:52 PM] Connecting to: http://api2.bitcoin.cz:8332/
[4/25/12 4:32:52 PM] Using Apple OpenCL 1.0 (Dec 23 2010 17:30:26)
[4/25/12 4:32:53 PM] Added Radeon HD 4870 (#1) (10 CU, local work size of 64)
[4/25/12 4:33:32 PM] ERROR: Invalid solution 1 from Radeon HD 4870 (#1), possible driver or hardware issue
[4/25/12 4:33:48 PM] api2.bitcoin.cz accepted block 1 from Radeon HD 4870 (#1)
[4/25/12 4:33:50 PM] api2.bitcoin.cz accepted block 2 from Radeon HD 4870 (#1)
[4/25/12 4:35:29 PM] api2.bitcoin.cz accepted block 3 from Radeon HD 4870 (#1)
[4/25/12 4:35:50 PM] api2.bitcoin.cz accepted block 4 from Radeon HD 4870 (#1)
[4/25/12 4:37:15 PM] api2.bitcoin.cz accepted block 5 from Radeon HD 4870 (#1)
[4/25/12 4:38:39 PM] ERROR: Invalid solution 2 from Radeon HD 4870 (#1), possible driver or hardware issue
mhash: 86.4/85.3 | accept: 5 | reject: 0 | hw error: 2

Basically it goes on and on like that, and I don't think I've had a valid solution yet. I know most people will just say "Apple sucks" or something, but I know that folks have had some success mining with iMacs. I have access to a LOT of them, so I'm curious if I can get this working.
Any ideas?

Topic: nothing but invalid solutions, Diablo OS X mining (Read 663 times)