Hi Sami,
Can you go to InfoView -> Preferences -> Preferred Viewing Locale ? And tell us what is selected.
What is the data type of object that you are trying to use as prompt ? If its date then do following step:
--> Side by Side, go to universe remove any formatting on the object you are trying use in prompt. Export universe and create a temporary report with just one object (which you want to use as prompt) to see what date value is being shown in report.