If you are using CS2009 you may be confused what are the differences between CSharp.pup and MicrosoftCommerceDefaultSiteWithSampleData.pup files. The following thread describes the differences:
“CSharp.pup : was released with CS 2007, It has only the schema and the webservice configuration.
MicrosoftCommerceDefaultSiteWithSampleData .pup : was released with CS 2009, It has the schema required for 2009 ( eg. store object & virtual earth configuration) & the sample data along with the webservice configuration.
MicrosoftCommerceDefaultSiteWithNoData .pup : was released with CS 2009, It has only the schema required for 2009 ( eg. store object & virtual earth configuration) and the webservice configuration.“