In reply to perumallatarun:
It would help to show the error message and the statement causing the error.
SystemVerilog has restrictions on what can be assigned using an NBA based on a number of different things. No NBA’s to
- any nets
- variables with automatic lifetimes
- elements of dynamic arrays, queues, or associative arrays.
So you also need to show us how the variable you are trying to do an NBA is declared.