/*Mplus runner*/
/*sorry, I forgot if either of these two lines worked or not*/

option xwait xsync;

/*I think you can use this one if you have spaces in between path names*/
X %unquote(%str(%'mplus "C:\controlfile.inp" "c:\outputfile.out" /y%'));         

/*otherwise*/
x "mplus 'C:\controlfile.inp'";