1) If you tring to play a file that is not supported by mIRC (a .mpg or a .txt for exemple), mIRC said that the file doesn't exists :
* /splay: no such file 'Path\file.ext'
You can reproduce this by typping something like :
Maybe mIRC can display that he can't open the file
2) Exemple is better that my bad explanation :] :
//var %a 1 | while (%a <= 5 { inc -s %a } | echo -a end
This return * /while invalid format (as it should) but :
//var %a 1 | while %a <= 5) { inc -s %a } | echo -a end
This WORKS !
//var %a 1 | while %a <= 12) { inc -s %a } | echo -a end
This increase %a to 2 and break the while
//var %a 1 | while %a <= 20) { inc -s %a } | echo -a end
This increase %a to 3 and break the while
//var %a 1 | while %a <= 9) { inc -s %a } | echo -a end
This increase %a to 90 and break the while
//var %a 1 | while (%a <= 9 { inc -s %a } | echo -a end
This return * /while invalid format
Edit : tested on 6.3 and 6.21