We have recently written an Excel utility which finds the differences between
Excel workbooks. If you want to have a look at the utility it can be found at
http://www.florencesoft.com and http://www.florencesoft.com/exceldiff.html

Users in continential Europe had problems when they were using our tool with
an English language version of Excel but had regional settings such as
French-Belgium or German-Austria.

Microsoft say these problems can be fixed by changing the current thread's
locale from whatever has been inherited from the control panel to US-English.

However we found other problems to do with the way commas in text strings
were handled as well. We want to post this as a tip for other people if they
start getting problems with users in continential Europe when using .NET and
Excel.