This happens if a NPC text file has a Code in it that does not match to the whole coding system.
For example, if I have a Code that looks like this:
It crashes SMBX with the Error Message "Type Mismatch". There are like unlimited possibilities that let it happen so make sure that everything you have typed in your NPC Text Files are correct.
Oh and I surely do not recommended to use Decimals in your code like this:
Or else it goes either incredible fast or it crashes with a error message. Check this Forum Topic Link for further Information on Decimals: http://www.supermariobrosx.org/forums/v ... =69&t=1659
Make sure that you have checked every NPC Text Files to prevent "misleaded" codes that doesn't match with SMBX. This is why the Error is called "Type Mismatch".
If that's not the issue, let us know!