Why "exec ffmpeg..." not working in windows?

application live2 {
			live on;
			record off;
			exec_options on;
			exec "C:\Nginx\ffmpeg.exe" -i rtmp://live.mysite.com/live2/$name -async 1 -vsync -1 -c:v libx264 -acodec copy -b:v 256k -vf "scale=480:trunc(ow/a/2)*2" -tune zerolatency -max_muxing_queue_size 1024 -preset veryfast -crf 23 -g 60 -hls_list_size 0 -f flv rtmp://live.mysite.com/hls/$name_low -c:v libx264 -acodec copy -b:v 768k -vf "scale=720:trunc(ow/a/2)*2" -tune zerolatency -max_muxing_queue_size 1024 -preset veryfast -crf 23 -g 60 -hls_list_size 0 -f flv rtmp://live.mysite.com/hls/$name_mid -c:v libx264 -acodec copy -b:v 1024k -vf "scale=960:trunc(ow/a/2)*2" -tune zerolatency -max_muxing_queue_size 1024 -preset veryfast -crf 23 -g 60 -hls_list_size 0 -f flv rtmp://live.mysite.com/hls/$name_high -c:v libx264 -acodec copy -b:v 1920k -vf "scale=1280:trunc(ow/a/2)*2" -tune zerolatency -max_muxing_queue_size 1024 -preset veryfast -crf 23 -g 60 -hls_list_size 0 -f flv rtmp://live.mysite.com/hls/$name_higher;
		}
		
		application hls {		
			live on;			
			hls on;				
			hls_type live;			
			hls_path C:/nginx/html/hls2; 
			hls_fragment 5s;		
			hls_playlist_length 30s;	
			hls_sync 2ms;			
			hls_continuous on;		
			hls_nested on;			
			hls_cleanup on;			
			hls_fragment_naming system;	
			hls_fragment_slicing plain;	
			hls_variant _low BANDWIDTH=288000;	# _low		- Low bitrate, sub-SD resolution
			hls_variant _mid BANDWIDTH=448000;	# _mid		- Medium bitrate, SD resolution
			hls_variant _high BANDWIDTH=1152000;	# _high		- Higher-than-SD resolution
			hls_variant _higher BANDWIDTH=2048000;	# _higher	- High bitrate, HD 720p resolution
		}