If you are suing IE to run the install wizard, try using a differant browser, IE may not be showing the full error.
If this is your local computer, you may also need to configure IIS to show the full error:
1) Go to Control Panel > Administrative Tools
2) Open the IIS control panel and open the ASP option
3) At the top of the ASP control area select Display: Friendly Names
4) Now go down to the Compilation area and expand Debugging Properties
5) In debugging properties make sure to set Enable Client -side Debugging, Enable Server -side debugging, and Send Errors to Browser to TRUE. Make sure to click the Apply on the right side of the page.
6) After setting the debugging you must go back to the IIS control panel and using the controls on the right side restart the server.
This will enable debugging info to display when an error occurs.