Upload iviewer app to Iphone 3G s

Hello CF group,

Yesterday I was handed two 3gs phones for the project I have been
working on.
Last night I just got a black screen on the phones. I figured it was
Win 7 64 bit.
Today I tranfered the project back to my development XP machine and
this time I get a message:

Can't read GUI file at URL (in win XP)

I do not get the above message when attempting the upload from Win 7
(just a black screen on the ipod)

The Ipod touch (my development device) loads the same file without a
hitch (from Win 7 and XP)

I have registered all devices and they come up under manage devices.
I can ping the iphones from within the network so that rules out 3g
only issue.

It seems to me like a 3gs issue.
Perhaps I have left smth out?

Has anyone experienced this?
Any ideas?

Thank you

Nahshon