I assume the issue here is trying to find the DefaultClientScript property. It appears that the DefaultClientScript property of the document object has been removed since the beta version of VB
2005. I was never able to confirm the removal, but it is not available in the released version anymore that I can find. Here is a what happens behind the scenes if you would set that property.
You can switch to source view on the default.aspx page. That is at the bottom left of the design area. In between the start and end <head> tags put the following
<meta content="text/VBScript" http-equiv="content-script-type" />
Then when you create your client script it will default to vbscript. That is what selecting the defaultclientscript would do for you.
Here is more info from MSDN2
Hope this helps. I will ask to have this listed in the errata.