First of all, if you are a current Baan customer you can contact support at firstname.lastname@example.org
or at the USA toll free number 800-678-3448.
Here's a few suggestions:
Are you trying to connect attached or detached? If it is attached and you're getting this error it could be that the servername or username/password in the registry may be wrong. Or if you're connecting thru oracle may be your TNSNAMES.ORA is not correct. You can use odbcinfo which is in the CRM program folder to check if you are able to connect to the server. Or can use sqlplus for oracle or sql server tools to check if you can connect to the server.
If you are trying to connect detached, then you have to login as the username/password you entered during install. If detached using the demo profile, then you can try aurum/aurum or chris/cj as username/password.
If you are not sure of what you entered as username/password then you need to look at the basedb.sql under the MSDE if it is 4.3 or install.wts if it is earlier version. That will give you your username/password to login to the detached database.
That's all I can say. Other than that you will have to find it in the documentation or contact support as mentioned above.