For some reason when I tried simulate the LCD wrote "Developed by electrosome" (the website I used the code from), and then it was supposed to display a distance using the ultrasonic sensor test pin. But it simply doesn't. just blank.

 

You mention that you "simulated" it. Do you mean that you ran it in a simulation software or that you actually built one? What is RV2 connected to? I have never seen that in an ultrasonic sensor circuit before.
I tried to find your project on "TheEngineeringProjects.com" website but I could no without enrolling. A listing of the software would give us a few more clues to help you.

 

Did you use the MikroC or XC8 compiler??? Also that ultrasonic module isn't in the Proteus library.

 

Is your "other" thread linked to this... As that sensor needs the library from their website... Hence the child warnings..