Error Installing Second SQL Instance

I am trying to install a second instance on my 2008 R2 server running SQL 2008 R2.  During setup, Im getting this error:

Rule "Consistency validation for SQL Server registry keys" failed.

The SQL Server registry keys from a prior installation cannot be modified.  To continue, see SQL Server Setup documentation about how to fix registry keys.

Any idea how to fix this?  I checked the logs and it stops at this point:

2013-12-06 12:01:19 Slp: Launching external tool: C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\SQLServer2008R2\x64\FixSqlRegistryKey_x86.exe
2013-12-06 12:01:19 Slp: ------------------------------------------------------------
2013-12-06 12:02:33 Slp: ------------------------------------------------------------
2013-12-06 12:02:33 Slp: C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\SQLServer2008R2\x64\FixSqlRegistryKey_x86.exe exit code: -1073741701