I'm having the exact same problem, although on my desktop. If I find the answer I'll let you know. I found this question when searching for the solution.
Ok, go here: http://kb2.adobe.com/cps/403/kb403264.html
This didn't work for me but you can give it a try. You'll notice that the manual download for Shockwave doesn't list Vista.
I may have to wait for Windows 7. Vista sucks.
UPDATE: Here's a better answer. I'm going to try this tonight. http://www.informationweek.com/news/windows/operatingsystems/showArticle.jhtml?articleID=207801611
ANOTHER UPDATE: I got it to install! This is what you'll need to do. First login as the administrator. This is the admin account that you would have set up when you first got it. Then go to the Control Panel - User Accounts. Click the link to turn on or off User Access Control (aka UAC). Turn it OFF. Choose to restart later. Then open IE. Go to Tools-Internet Options-Security. Change the level to Medium. Then go into the Custom settings and change ActiveX controls to enable or prompt. Close IE and restart. Login again as the admin account and try the Shockwave install again.
This worked for me! I'm so happy because now I can play iSketch again.
Just be sure to UNDO everything you did once you have it installed.
I got this info from http://technet.microsoft.com/en-us/library/cc709691(ws.10,printer).aspx. The section heading is To turn off UAC.
Good luck!