The dress is Dynamic and needs to be run through the cloth room.

Here are some tutorials on how to use dynamic clothing in the cloth room:

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2665209

http://www.philc.net/CC_sampleVideo.htm

http://www.poserfashion.net/howvic3dress1.htm

http://drgeep.com/p5/cr/cr.htm

Here are some links to some great FREE dynamic clothing:

http://www.renderosity.com/mod/freestuff/index.php?username=mapps

http://www.renderosity.com/mod/freestuff/index.php?username=svdl

http://www.renderosity.com/mod/freestuff/index.php?username=Stegy

http://www.renderosity.com/mod/freestuff/index.php?username=carib98

http://www.renderosity.com/mod/freestuff/index.php?username=teyikung

It's also possible to make conforming clothing into dynamic clothing:

http://www.renderosity.com/mod/tutorial/index.php?tutorial_id=868

And it's possible to take a conforming outfit and work with it in the cloth room so that parts of it act dynamic.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2517340&page=1

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi