From the last OATS release notes available in the C:\OracleATS\docs directory:
4.1 Oracle Functional Testing/OpenScript
Oracle Functional Testing’s OpenScript scripting platform has the following system
■ Operating System (32-bit and 64-bit versions): Windows XP, Windows Vista,
Windows 2003, Windows 7, Windows 2008, Windows 2008 R2.
■ Memory: Minimum 1 GB
■ System: x86, 32-bit or 64-bit processor, 2.6 GHz or faster
■ Disk Space: 4 GB minimum
■ Browser: Internet Explorer 7.x, 8.x., 9.x; Firefox 3.5/3.6, 6.x, 10; Chrome 27+
■ Java Runtime Environment: JRE 1.6 minimum (up to build 38), JRE 1.7 (up to build
So basically, it's not supported... Can you try with another JRE version?
As always don't forget to run OpenScript as administrator on W7/8 or equivalent