sql5005n: Unable to init API env

When I try to import a DB2 catalog to Toad for db2 4.7, I got sql5005n: Unable to init API env error. Database alias combo is not populated. This happens with 64 bit toad whereas 32 bit version is working fine. I had this problem under windows 8.1. Solution: Forget catalog import on toad. Run all below steps with administrator right 1. Install db2 64 bit client to windows. 2. Install Toad 64 bit 3. Edit registry , change HKLM\Software\Wow6432Node\QuestSoftware\Toad For DB2\4.7\DB2COPY key to DB2COPY1 (initial repository for IBM client) 4. Run IBM DB2 configuration assistant 5. Import catalog by using configuration assistant 6. Run toad, database alias combo is populated.