For three days I fought to be able to connect our Linux intranet server to our AS400 database through ODBC and PHP on Mandrake. I installed everything I thought would work but I still got a: odbc_connect(): SQL error: Missing server name, port, or database name in call to CC_connect., SQL state IM002 in SQLConnect
Note that isql was working great but php was failing to connect.
The solution:
I located and found a PHP module called php-unixODBC (to oppose with php-odbc). Once installed (even though it wasn't for the right version of PHP), I realised it didn't place the file properly. The ini file was in /etc/php/ instead of /etc/php.d/, so I moved it there and renamed the old /etc/php.d/36_odbc.ini to /etc/php.d/36_odbc.ini.sav, so that I now had /etc/php.d/36_unixodbc.ini. I restarted the httpd server and now I was able to access the as400.
If you have questions, email _artaxerxes2_at_iname_dot_com (sans the underscore).