Problems in filling in given name during ETS registration

My given name in passport is Prathyush Levakumar

When i am filling in Prathyush Levakumar in the given name column, it is not accepting it. In what format am i supposed to fill it. Do i need to replace the space in between the names with some other symbol? Pls advice.

No, I suggest you fix your passport first and then register. I have replied in other thread. You need to have Surname field in your passport to avoid future issues.