Conflict Between Chuck Smith and Rick Warren?

Two of Southern California (and the world's) most influential pastors seem to be in conflict for reasons that haven't yet been made clear. SmartChristian.com points us to a posting on Chuck Smith's Calvary Chapel product website which has the following information:

DISCONTINUED ITEMS
The teaching and positions of Rick Warren have come into conflict with us as Calvary Chapel. Pastor Chuck has directed us to discontinue this product effective immediately. The following items are now longer available through Calvary Distribution:
• 0310205719 The Purpose-Driven Life
• 0310209072 The Purpose-Driven Life Audio Cassette
• 0310247888 The Purpose-Driven Life Audio CD
• 0310255252 The Purpose-Driven Life Large Print Paper
• 0310805554 The Purpose-Driven Life Deluxe DuoTone Journal
• 0310803063 The Purpose-Driven Life Journal Hardback
• 0829737863 Spanish The Purpose Driven Life
• 0829738711 Spanish The Purpose Driven Life Journal
In light of the above, we are also discontinuing:
• 1000000945 One Minute Meditation
• 1400070511 There is a Season
Returns on these products will be subject to our normal return policies. Please contact our customer service department with any additional questions.
Phone: 800-444-7664 Fax: 714-641-8201 Email: mail@calvaryd.org Web: www.calvaryd.org

Chuck has also recalled a book he wrote which endorsed Purpose Driven Life. Interesting.

There is no explanation why Chuck Smith suddenly has a problem with Purpose Driven Life or Rick Warren, at least none that I've found. I'm wondering if Warren's recent foray into what certainly looks like liberal politics (here and here) might be driving Chuck's reaction. Otherwise, I don't know of anything in the PDL materials that could be considered a conflict with anything that Calvary Chapel teaches.

Anybody with more information, please post a comment. I'm curious as to what's really going on. I'd hate to think that this was just some kind of professional jealousy.