In Windows XP the csv field separating character is determined by a 'Regional options' setting which affects how .csv files are saved which in turn might render the files incompatible with the templates used in Bika. See the different import file formats and examples on the downloads page at Bikalabs.org

To set your Windows XP to the corresponding setting, navigate via the Control panel from the Start menu and select Regional and language options. Click [Customise] and set the List separator to the correct character and press [OK] 

Thanks Rickus Adams at BBK laboratory