I ran into this problem, and tried everything that everyone suggested.
After carefully debugging the installer with a series of message
boxes, I traced the issue back to the way the installer is being
called. Apparently, the install sub was being called anytime the
installer was run, e.g. uninstall, rollback, install, etc. I had to
put in some lines at the top that checked to make sure that the
install sub was being called at install time and not at any other
time, like this:

If Not (Me.Context.Parameters.Item("action") = "install") Then
Return
End If

Hope this helps.

[email]jcwiese[/email] (Jim) wrote in message news:<1b998b5f.0306191101.56c34ba5posting.google. com>...
> Scott,
> I ran into this very same problem, and it was because I was passing
> data that should have been escaped :
>
> /SERVERNAME=[SERVERNAME]
>
> ... should have been
>
> /SERVERNAME="[SERVERNAME]"
>
> ... and since when choosing a file, the installer will pass a
> backslash which would actually escape the double quote:
>
> (eg.)
> The format : /TARGETDIR="[TARGETDIR]" would produce:
>
> /TARGETDIR="C:\program files\My Company\MyProduct\" <-- escaped
> quote
>
> The format : /TARGETDIR="[TARGETDIR]\" would produce:
>
> /TARGETDIR="C:\program files\My Company\MyProduct\\" <-- escaped
> escape which is fine