If IN[33] is what makes your program number 1 run in CELL.SRC, then keeping it HIGH even after the program finishes will produce the message "Wait for not Input 33"
Otherwise the program would just repeat itself over and over again.
If you want to tell the PLC that the program has started and there is no need to keep sending IN[33] to robot, you can check the signal $IN_HOME.
It is fair to assume that when robot is not $IN_HOME anymore the program has started. And when the robot is back $IN_HOME the program has finished.
You could also add some "handshake" at the end of your robot program to make sure that a specific program has finished and not just any random program. So you can create some signals / assign some inputs and outputs to set high when the program has finished.
PROG_1_DONE = TRUE
WAIT FOR PLC_Acknowledge
PROG_1_DONE = FALSE