I fixed the problem by changing this to strdup([string UTF8tring]). Then, after the call to AEWP, I cycled back through the args again and freed each one like so:

// BEFORE
const char **argv = (const char **)malloc(sizeof(char *) * [args count] + 1);
for (NSString *string in args) {
argv[argvIndex] = strdup([string UTF8String]);
argvIndex++;
}
argv[argvIndex] = nil;

// Insert call to AEWP here

// AFTER
for (int i = 0; i < argvIndex; i++) {
free(argv[i]);
}
free(argv);

Hope this helps someone!