I'm amazed my search-fu didn't answer this, but here goes:
QUESTION: Does Dimensional Anchor prevent a creature from going incorporeal?
SITUATION: The resident sorceress hit an assassin with a Dimensional Anchor. Said assassin had the ability to go incorporeal. I ruled that Dimensional Anchor did not stop this ability, but promised to check on the messageboards.
Dimensional Anchor: A green ray springs from your hand. You must make a ranged touch attack to hit the target. Any creature or object struck by the ray is covered with a shimmering emerald field that completely blocks extradimensional travel. Forms of movement barred by a dimensional anchor include astral projection, blink, dimension door, ethereal jaunt, etherealness, gate, maze, plane shift, shadow walk, teleport, and similar spell-like abilities. The spell also prevents the use of a gate or teleportation circle for the duration of the spell.
A dimensional anchor does not interfere with the movement of creatures already in ethereal or astral form when the spell is cast, nor does it block extradimensional perception or attack forms. Also, dimensional anchor does not prevent summoned creatures from disappearing at the end of a summoning spell.
Ghostly Form (Su): This creature can become incorporeal (including all of its gear) for 14 rounds per day as a swift action -- returning to solid form is a free action. The rounds per day need not be consecutive. This ability cannot be activated in areas of bright light, and while in ghostly form the creature cannot enter such an area.
My take is that Dimensional Anchor provides a fairly comprehensive list, and incorporeality is not on that list, so my ruling (so far) stands.
Waiting to see how others see this...
Dimensional Anchor only prevents dimensional travel. Notice that all the effects include dimensional travel somewhere: blink means hopping back and forth between the material and ethereal plane, shadow walk means going to the shadow plane, teleport means going briefly to the ethereal (at least I remember that of 3.5) and returning to the material.
Incorporeal means just changing the physical composition, like gaseous form, like shapeshifting. Sure, it grants new possibilities of movement, but are not "dimensional".
I don't believe it blocks incorporeality
It does not block it. Incorporeal is just a creature subtype. It does not require planar travel.