TOAD for Oracle and Windows 7: Can't initialize OCI. Error -1

For me, This problem was caused by me setting ORACLE_HOME windows environment variable (permanently). I set this whilst trying to get "emctl" to work.

Once removed, TOAD worked fine.

I opened toad with administrator privilege (Right click -> Run as Administrator). The problem solved.

Thanks a lot!

Removing the ORACLE_HOME from the environment variables (system) worked for me.
TOAD is now working fine.