OK, that helps - but as a VBScript novice I'm still stuck!

The output I'm getting is now

Building project step 'Increment Build number'...
234
497
Error at Line 5, Column 1 (Object required: 'DateDiff(...)')

The script fragment is

' set the version number for the various features
Builder.LogMessage DateDiff("d", Now, #1/1/2006#)
'Set Origin = DateValue("1/1/2004")
Builder.LogMessage DateDiff("d", #1/1/2004#, Now)
set ourday = DateDiff("d", #1/1/2004#, Now)

It looks rather as if, despite the error complaining about DateDiff, it's some kind of type incompatibility. Any more help please?