Liquidflux

Maybe you could try the opposite? Try making a Wurmple with the last bit between 0-4 to see if that information is correct... or you could try another Wurmple.

I tried changing the PID to 2716475891 to see if that indeed made a difference as the last bit after following the instructions detailed in that guide is 1. However, it made no difference and the Wurmple again evolved into a Silcoon. I have attached the current Wurmple's .pkm file if that makes solving things easier.

wurmple.pkm

Wurmple evolution is based on its personality value. I don't really know how to calculate exactly how you find whether it's Silcoon or Cascoon.

The information on calculating it is listed here: http://www.smogon.com/forums/showpost.php?p=1442211&postcount=20

Following the steps of that guide, the PID converted to hexadecimal is 21EAA1F3, the last 16 bits of which being A1F3. That converted to decimal is 41459 the last digit of which is 9 which SHOULD mean that it evolves into a Cascoon. The fact that it doesn't is the reason I am stumped.

I have a (wild) Wurmple on Pokemon Platinum that evolved into a Silcoon which I already had so I used pokesav to turn it back into a Wurmple, resetting its ability, moveset and level. I then changed the IVs until I got a male PID (nature didn't matter) that would evolve into Cascoon and everything came out legal on the legality checker. However, when I levelled the Wurmple up, it evolved not into a Cascoon but a Silcoon. Can someone please help me figure out what went wrong?

The PID I have is 569025011 and the IVs are:

HP: 18

Att: 25

Def: 17

Sp. Att: 28

Sp. Def: 17

Spe: 20