After two days of googling and browsing forum posts I finally got it to work, so I want to share how I got around the errors:
1)
Error: [unixODBC][Oracle][ODBC][Ora]ORA-12545: Connect failed because target host or object does not exist
Solution: Just set the TWO_TASK environment to the value of your SID.
2)
Error: [unixODBC][Driver Manager]Specified driver could not be loaded
Solution: I run a x86_64 system and so I had the 64bit version of unixODBC installed. After I switched to the 32bit version (of unixODBC
and the instantclient files) it finally worked as expected.
Hope this saves someone the time I had to spend to find it out.