I've tested it on 3 different computers.
#1 - 3.2 Ghz Pentium 4, 1024MB RAM.
#2 - 1.5 Ghz Dual Core Pentium, 512MB RAM.
#3 - 1.5 Ghz Pentium 4, 512MB RAM.
The best results and smoothest gameplay was achieved by the 1.5 Dual Core Laptop. With the longest time without any "hanging errors" of over three chapters.
It is pretty surtain you'll encounter one of these errors trough out playing the game. But what is also 100%, no 1000% surtain is that it will not occur during gameplay and only after you receive the end level code.
It is something really bad I know, but it seems to be the limit of RMXP's processing power. This always happens, I make a game that the game maker itself can't seem to handle.
I've got a few more ideas to either prevent or further limit these errors, and I'm even sending a help request to Enterbrain (Compagny that translated it).