Hi Arpit,
What do you mean by SAP 6.0 , is it ECC system?
Check in your source system with RSA1.
If you are creating a new Cube , first see if you have any cube available in business content. most of the standard cubes meet normal requirements.
So first check you are in an R/3 system of BW system.
Revert for further clarifications.
Regards,
Sudhir