no there is no error message, I pressed Control+h in all scripts which have to do with it, which are two. Where should the error message be, in a Status window? I can't see anything.
That should be alright. Other scripts aren't loaded, only these two. Otherwise it's plain mIRC

//EDit:
Ok...I just wrote a simple script

Code
alias testo {
  if ( $input(lulu,yv,lala) == $yes ) { echo -a hello } 
}


doesn't work.

Code
alias testo {
  if ( $input(lulu,y,lala) == $true ) { echo -a hello } 
}


works! So for me the Problem is solved and mIRC changed it's behaviour about this