sadafkhan, I managed to do the conversion using the Hyper-V in Windows Server 2008 R2.
With the offline VM hosted on Hyper-V.
I used VMware vCenter Converter Standalone 5.5.3
Even using the 5.5.3 version, the Hyper-V for Windows Server 2012, has the same error.
"The version of the selected Microsoft Hyper-V is not supported. Select an Earlier version of Microsoft Hyper-V Server or another supported source type."
I had to add the Hyper-V Role on a VM with Windows Server 2008 R2 for the conversion work.