As Wims pointed out, this cannot work without the /run command.
/run [-np] <filename> [parameters]
runs the specified program with parameters.
thus
/run "C:\Program Files (x86)\winamp.exe" /Add "\\QUEUE" "%1"tells mIRC to
run the file
winamp.exe located at C:\Program Files (x86)\, with your
parameters aka winamp command line options.
As <filename> is a filepath-with spaces, you
have to put it in quotation marks, (Riamus2 stressed that point). mIRC would else take " C:\Program" " as <filename> and the whole " Files (x86)\winamp.exe" /Add "\\QUEUE" "%1" " as [parameters].
I don't use winamp, but I doubt you need quotation marks arround the command line parameter "\\Queue". Also note that mIRC will not evaluate the variable %1 to it's value if put in quotation marks. If the value of %1
has to be in quotation marks according to winamp command line options, use either $qt(%1) or $+(",%1,").
Just to make it clear,
if you omit the /run command, you're telling mIRC to execute a
command (internal command or scripted alias) called " "C:\Program " and with the
parameters " Files (x86)\winamp.exe" /Add "\\QUEUE" "%1" ".
"C:\Program Files (x86)\winamp.exe" /Add "\\QUEUE" "%1"As mIRC does not find such a command it sends the whole line to the server - just like any unknown command.
The server, in return, does not know the command either. He's thus returning an error message (raw 421) about the unknown command (wherein the additional parameters are left out), and mIRC does display the server's error message:
"C:\Program Unknown command