Have you downloaded and run ssgodbc (to be found in the main menu of the Informatica Network window under Resources -> Debugging Tools) for your platform? Usually this tool gives very clear error messages.
i have already use the SSGODBC, with the same error.
And you did double-check that you keyed in the user ID and the password correctly for ssgodbc?
were you able to get this issue solved?
Can you verify on the below points:
1. Is there any issue from the Database side
2. Is there any network issue?
3. Double check on the user name, password , Database server IP/Hostname(try using both one by one i.e hostname and IP)
4. Is there any firewall in between?