I downloaded the latest Oracle versions for studying. (I don't have a metalink account because I am actually not working)

I want to install Oracle Database 11g + Oracle Developer Suite 10g on the same Windows XP Desktop. I did the following steps :

- Install Oracle Database 11g in ORACLE_HOME "C:\oracle\product\11.1.0\db_1".
- Create a database DEV
- Startup database DEV, listener and configure sqlnet.ora+tnsnames.ora
- Connect to the database with sqlplus system@dev => connection succeeded
- Install Oracle Developer Suite 10g in ORACLE_HOME "c:\oracle\product\DevSuiteHome_1" and choose Installation Type "Complete (1.13 GB)"

When I install Oracle Developer Suite 10g I receive the following error:

Oracle Developer Suite 10g ( cannot be installed into existing Oracle9i or higher Oracle Home.

I don't understand why I receive this error. Oracle Developer Suite creates a seperate Oracle Home, so I don't understand why the error says that it tries to install into an existing Oracle Home.

What must I do to solve this problem?