It just refuses to use it!

I downloaded one on here that was smaller than the original, filesize-wise. All I did was restore the original MSBin with the song titles so I could use it to match my own BRSTM collection. But the thing is, it freezes after Now Loading..., which comes after the strap screens. And when I bypass it and put it back on the SD card later, it freezes after I select a stage.

I've been trying to modify and use the damn thing for months, and no dice.

This is mind-boggling, my file is 387Kb and it just refuses to work. What am I doing wrong? I didn't even replace textures or anything, I just changed song titles and thus made the thing 2kb SMALLER.

Help please?  

Oh, and if you must know, I'm using StackSmash, Custom Expansion/Eternal Yoshi's maxed out CSS/The latest stable File Patch, an edited selmap and selcharacter.