I used Photoshop CS2's Merge to HDR function a few times last week. Each time I only used two RAW exposures with one full stop difference between the two, and it worked flawless.

Question: where your files shot in RAW and converted to 16 bit..?

We do not see things as they are. ǝɹɐ ǝʍ sɐ sƃuıɥʇ ǝǝs ǝʍ