To reproduce put this in your remotes:
Code:
alias test {
  if ($1 == blah) { echo -a $1 }
  if ($1 == blah { echo -a $1 }
}

and type this line:
/test a
And you will get an error like this:
* /elseif: invalid format (line 3, script.ini)
That (obviously) isn't right, since there isn't an elseif in the script.

If you type this line:
/test blah
and it works properly, with an error like this:
* /if: invalid format (line 3, script.ini)

Reproduced on mIRC 6.03.