Failed to import Data VUM 5.1

I try import ESX 5.0.0 u2 ISO-Image in VUM 5.1 .... the process end with failure -> "Failed to import data"

The ESX 5.1 Image was imported without Problem .... in the vCenter working ESX4.0 Build 244038 Host ..ready for Upgrade ... to 5.1 and 5.0 ... depends on HCL ... give Host have no Support 5.1.

Give a Problem Import for different ESXi 5x  Version in VUM ???