C/ODBC connex to external OLAP

I am attempting to connect the Navision Database to an external OLAP tool (cognos, excel) via a c/odbc connection. Application terminates with Error Message: …the memory could not be ‘read’. Current production platform: Native Navision database V3.01B Windows NT Excel 97 & 2000 Cognos Impromptu 5.0 Thanks for your assistance