Jayesh,
So the short of it is because 6.1 isnt supported on VMware. The first version that is officially TAC supported on VMware is 8.0.2. With that being said, for lab recreates and confirming you have successful backups, it can be advantageous to have a test setup in VMware. You should be able to install it on VMware to test certain features. The key for 6.1 will be to get the VMware requirements correct. Here are the spec's that we use in our Lab testing environment for 6.1.5:
1 - vCPU
2Gb RAM
80Gb Harddrive
Virtual Machine version 7
RedHat Version 4 32-bit
Hope this helps!
-Brett Fritzsch