Vincent,
I've not been using this program yet, but your problem entering coordinates reminds me of a similar problem I had with an other program (I'm Dutch as well).
Try and set the language of your computer and keyboard (temporarely) to English.
There may be a problem in how the program reads certain signs.
Edit:
Meanwhile I've used the program and indeed you have to switch to English in the country-settings:
(for us Dutch
) Start->instellingen->landinstellingen
Alter "Nederland" to f.i. Engeland (verenigd koninkrijk).
Probably you will have to restart the system.
Afterwards, don't forget to switch back to 'Nederlands' (Nederland) or certain values, decimals etc. will be shown in a 'false' format.