ODBC error 00000 in SQLConnect:

The Oracle 32 bit Client library directory was included in the LD_LIBRARY_PATH environment variable.

The odbcsql utilty was still showing the error:
Logging into "SBA_81_DSN" as "SADMIN" ...
ODBC error 00000 in SQLConnect:
Unknown ODBC error!
(native error 0).
Unable to login using specified ODBC parameters.

Cause

1. This error is usually caused by the Data Direct Oracle ODBC Driver used by Siebel applications, not being available for load by the process.

2. Siebel User has insufficient permissions and, as such, connectivity tests to the Database fails.

3. There are some strange characters at the top of the .odbc.ini file which indicates some corruption of the .odbc.ini file.

Solution

#	Likelihood_of Occurrence	Cause_for_this_could_be	Solution/Fix
1	This problem is likely to be encountered in any environment when ODBCSQL connection is not successful to make Database Configuration to work.	Starting from Oracle database 11gR2, however, as 32-bit Oracle client libraries are no longer shipped with the 64-bit Oracle database server or 64-bit Oracle database client media, the lib32 directory is no longer created in $ORACLE_HOME, and as such it is no longer sufficient simply to update the library path.	1. Verify that the Oracle 32-Bit client software is installed on your Siebel Server. See:Doc ID 1290695.1. 2. Include Oracle Client's lib directory in the LD_LIBRARY_PATH variable as set in the dbenv.sh file: LD_LIBRARY_PATH=<ORACLE_HOME>/lib32 export LD_LIBRARY_PATH 3. Check that the ORACLE_SID is set appropriately and export it 4. Test ODBCSQL connection. Once ODBCSQL works, the Database Configuration Wizard should also work. This Procedure is documented on the bookshelf in: Siebel Installation guide for UNIX > Configuring the Siebel Database > Configuring Connectivity to the Siebel Database
2	Siebel User has insufficient permissions	While it is possible to run the sqlplus tool successfully, a tnsping test fails with errors: Message 3509 not found; No message file for product=network, facility=TNS	Execute changePerm.sh to reset permissions on directories. The script (borne shell) loops through a hard-coded set of files and directories, extracts the "group" permissions, and set the "other" permissions the same as the group's permissions. By doing so, "other" users are able to execute these files and change to these directories (http://www.orafaq.com/wiki/ChangePerm_sh)
3	If .odbc.ini file has been edited using some editor other than vi or it has been edited manually and it was saved leaving some strange characters in the file	Some third-party editors may cause .odbc.ini file to corrupt leaving strange characters or user editing error.	1. Back up the .odbc.ini file and then remove the strange characters from current .odbc.ini file 2. Test connecting to the database using odbcsql 3. Run the Database configuration utility to create the database.

结果根据support 上建议，查看了 .odbc.ini 文件的头部，果然有奇怪的字符，删除后，再运行

odbcsql /s SBA_81_DSN /u SADMIN /p SADMIN

连接成功！