I have a HVR Z1, I was shooting in the Amazon Jungle a little dust get inside the lens. i could not shoot against the sun without seeing a spot. I took the camera for cleaning and they told me I have to change the whole lens..is that possible?

In a word, yes. I've had dust get in my professional lenses but at least they can be serviced. The lens on the Sony may not be serviceable and therefore must simply be replaced. Others might know better.

Unfortunately I think it's true that the lens is a sealed unit which can't be serviced. This was discussed in a similar thread recently. See these photos which show the lens as a separate self-contained module:

http://www.camcorderservice.nl/sony_fx1.htm

But since it is sealed, I wonder how the dust got inside?