Tips & Tricks: Common problem when uploading data
If you are uploading data from a CSV file (created in MS Excel) via the built-in wizards in Salesforce.com, in some cases you're unable to select the right field mapping. All fields then appear as one long field definition:
This is because MS Excel uses a semicolon (;) instead of a comma as a separator when your Windows language settings are set to Dutch.
The easiest workaround for this is saving your import file as a "Text (Tab delimited) *.txt" file:
And importing the file in the same way as an CSV file. Salesforce will detect the format and will allow you to choose the right column mapping.