problems loading LISP routines

We have just upgraded 6 licenses to 9.1 and we have a lot of custom LISP routines (maybe 100) and custom menus and shortcuts all of which came over in a .CUI file and load up fine.

In a new drawing and in our .DWT template all menus and LSP load and work fine

However when an existing drawing created in earlier versions of Intellicad (and saved as Rel.2004 or 2010 etc) is opened I get the following message and all my shortcuts and LISP routines stop working on 5 of the 6 PC's. It will only work on one PC and I cant work our why? is there a setting I am missing in config or has the program not installed properly?

The error message in the command line on the 5 machines where the LISP routines wont load when an existing drawing is opened is

Warning: Can't restore AcDbScale from proxy

an I can only use the standard menu and no shortcuts or LISP routines

Any solutions?