Raised the issue with Oracle Support and got the following response:
Unfortunately, 10205 Grid Control is only certified with (2.2.0.0.0, 2.1.5.0.0, 2.1.2.0.0)
Please upgrade to 12c Cloud Control ,
also
Please review the following oracle article ..
How to Enable Oracle VM Management Pack in EM Grid Control 10.2.0.5 (Doc ID 1125013.1)
| 06 Build VM Server Manually | 08 Upgrade to OEM 12C |