While setting up additional company to test the intracompany transaction, i ran into the following error message when i clicked apply "java.sql.SQLException: ORA-20001: HR_7220_INVALID_PRIMARY_KEY: ORA-06512: at "APPS.HR_ORGANIZATION_API", line 4872 ORA-06512: at "APPS.GL_LEDGERS_PKG", line 111 ORA-06512: at line 1". Any idea how this can be resolved even though in the legal entity window, all the two companies are showing under the balancing segment for the legal entity.

It will be help if you specify when exactly you are getting this error. Is this error coming up when you try to complete the Accounting Setup or when attempting to "Complete" Balancing Segment Value Assignments? "While setting up" is not very explanatory.
Based on your reply I might suggest you to check your business group organization setup. Or it could be a
Bug 6794638 for which following patches are available:
For R12.0.x : Patch 6794638 R12.PER.A
For R12.1.x : Patch 8768005 R12.PER.B

Thanks a lot. I applied the patch and its working now.

Good to know that the problem is fixed.

I am getting this error too. How can I get this patch? are they only available on metalink?

Yes patches are available to download from metalink.

Is there any way of getting a cheap metalink account? In some forums I have read that buying some "cheap" products from Oracle store enables you to basic metalink access. Is this true? Any suggestions?

Possible options: 1. Get database personal edition with support 2. Get partnership.

Thanks!