I agree with MC and OR. Because of the high frequency, intensity, and volume, local tendons/muscles will become inflammed because of the workload. Errors in form can cause or exacerbate the issue, but isn't always the single reason for inflammation.
If you like the frequency and intensity of the lifts, I'd first spend some more time with the rehab/prehab methods MC mentions: message, heat/ice, anti-inflam before and after training, and some light compression/warmth during training (light wraps or knee sleeves).
I'd also look at other things such as strength/volume balances. Not only that but tight quads, tight hamstrings, glutes, or a lower back can all put more unneeded pressure on the knee. Greater strengths in one of these areas can create tightness in that muscle and/or increase the strain in the opposing muscle. Or poor mobility in one region can do the same.
Not saying that is the case, but just be open minded to the cause of the issue.
My bet leans more towards your total workload (frequency, volume, intensity) and given that you push it so hard that your 'dead' by your 3rd week (deload) says a lot about the demands training puts on your body.
The changes that can be made to minimize the issue are as open to interpretation as is the specific causes of the issue. Reduction of frequency, reduction in intensity, longer deload, shorter loading period, greater focus on mobility, strengthening a weakness, etc, etc.
Edit: Facz makes great points as well.
Last edited by Pull14; 01-10-2012 at 11:31 AM.