Selenium Grid stuck after “Registering the node to hub”. It does not show any line as “Executing…”

I'm facing a strange problem: I'm trying to set up a hub on a my window machine and node on VM or switch them.

But if I use the exact same commands to start the hub on my test VM the registration process seems to take forever.
Normally, the node should receive status request and respond to the hub server. But the console stays blank after printing
and when i click on myip:4444/grid/register it show me error like :-
HTTP ERROR: 500

Problem accessing /grid/register. Reason:

Server Error

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I am using combination as :-

Command (window 7):
java -jar selenium-server-standalone-2.42.2.jar -host ip -role hub -port 4444

Command (ubuntu linux):
java -jar selenium-server-standalone-2.42.2.jar -host ip -role node -hub ip:4444/grid/register -port 5555

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I also have tried :-
Command (window 7):
java -jar selenium-server-standalone-2.39.0.jar -role hub

Command (ubuntu linux):
java -jar selenium-server-standalone-2.42.2.jar -role webdriver -hub ip:4444/grid/register -port 5566

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I also have tried :-
Command (window 7):
java -jar selenium-server-standalone-2.39.0.jar -role hub

Command (ubuntu linux):
java -jar selenium-server-standalone-2.39.0.jar -role node -hub hubip:4444/grid/register -browser browserName=firefox,platform=LINUX -remoteHost nodeip:5555 -maxSession 5