Do you see the output pin change between high and load at the output pin of the mcu?
use larger delay, it will help you observe the output.
A pull-up has to be used, if you didn't enable the internal pull-up resistor then add an external one.
Disconnect the ULM2003 input from the mcu and connect it to a LOGICSTATE (you can find it in the add components screen, debbuging tools category), change the input to 1 and see if the output works.
Check if your relay is 5v (G2R-14-DC5).
Check if the voltage is set to all voltage sources (default is 0v)
Alex