Solution
One requirement in any SPICE simulator is that there must be a node 0 (ground) somewhere in the circuit. Since you connected a resistor directly to a multimeter, Multisim auto-node naming likely called the wires node 1 and 2. When you simulate the circuit, the SPICE engine does not see a node zero and therefore, it prompted you with the error message.
To get around this, double-click one of the wire and to open the
Net Properties dialog, in the
Preferred Name enter 0.