When running Crystal Reports that use Microsoft Access for the data source and the report is using an ODBC DSN the report might get an Error 012. If the DSN is using a mapped drive then the IIS user will not be able to view the mapped drive. Change the DSN to use a UNC in the format of \\ServerName\Sharename and make sure that the Share has permissions for the Network Serive user. This will allow the report permissions to the folder that holds the Access database.