do I need TNS_NAMES added as a variable or am I good?
TNS_ADMIN, I assume. No it's not required.
You could put the tnsnames.ora file in the instantclient folder i.e. same as where PATH points. If you want to use local naming that is. If you use Easy connect naming instead, you might do without tnsnames.ora.
I also checked my "Path" to make sure that the directory string was first as well as exactly case sensitive to the actual path. I checked the registry for the Oracle ODBC driver in the Wow6432Node and it to is exactly what it should be (pointing to the correct folder for the sqora32.dll and sqoras32.dll files. I entered the commands on the command line as you indicated.
There has to be something else I'm missing. Again Windows 7 64 bit and I'm using the 32-bit download from OTN. I've unzipped both the "Basic" and "ODBC" files in the same folder as a subfolder in my C:\oracle file location. I've then run the odbc_install.exe as an Administrator (fine no errors)...I've also added network\admin as subfolders to the instantclient_10_2 folder and placed SQLNET.ORA and TNSNAMES.ORA into the folder and pointed TNS_ADMIN in my system variables to it.
What on earth have I missed...I know it's going to be something that makes me feel stupid.
When trying to add a system DSN I get: "The setup routines for the Oracle in instantclient10_2 ODBC driver could not be loaded due to system error code 126: The specified module could not be found. (C:\oracle\instantclient-basic-win32-10.2.0.5\intantclient_10_2\sporas32.dll).
When trying to add a File DSN I get: "Error Cannot Load Resource File sqresus.dll"
I get either when trying to add the listed Driver from the 32-bit ODBC Data Source Administrator from Windows 7. The driver shown in the DSN menu shows up as "Oracle in instantclient 10_2"
Previously had the Universal Installer 18.104.22.168 install Oracle8i Client 22.214.171.124.0...This archaic setup wouldn't run which is why I uninstalled it...Although I'm aware there may be some residual files that weren't uninstalled.
I just had the same problem and figured it out with the tool "Dependency Walker" (http://www.dependencywalker.com). When you load the DLL "sqoras32.dll" into Dependency Walker then you'll see that the Windows DLLs "MFC71.DLL" and "msvcr71.dll" are required. These files are not by default installed on a Windows 7 x64 system. So just download the mentioned DLLs (e.g. from http://www.dll-files.com/) and put them into the Oracle Instant Client folder. Now everything should work fine!
So the error message has nothing to do with not finding "sqoras32.dll" - the registry entries linking to the file are correct. The real problem is the missing dependent DLLs. What a pain in the a**! ;)