Excel constantly "calculating" for United Kingdom Users but not US users

Hello, I've created a quote template that was originally used only by users here in the US. Now, users in the United Kingdom need to use it. The template uses macros and forms to navigate through the template. Users in the US do not have any problems, however users in the UK are having problems. Anytime they open up a form, code needs to run, however it is causing Excel to constantly "calculate" which renders the tool nearly useless. The users in the US are not experiencing this problem. The settings in Excel are all the same for all users as they all use the same VMWare remote desktop sessions. The UK users do have the UK keyboard settings. I am unaware of any other differences in their setup. Any reason why the UK users are stuck in the "calculation" mode when code is run even though the US users do not experience the problem when the same code is run?

have the UK users made it a Shared Workbook? this will grind a workbook with macros to a halt.

No, this is a read-only file. I believe the issue is has to do with the "language" settings in Windows XP and Windows 7. I changed mine to English (United Kingdom) within the "Regional Options" tab (of the "Regional and Language Options" within Windows XP Control panel) as well as changed it within the "Advanced" tab of the "Regional and Language Options. The section within the "Advanced" tab is called the "Language for Non-unicode programs". It appears that by making this last change to the "non-unicode programs" is the one that affects the excel file.