[FFmpeg-user] Syntax problem for specifying files(?)

[aviv solodoch]

Hello

I'm trying to create a movie from a series of .png files.
The file names are of the form "NWAT_Vort_GB_xxxx.pg",
where xxxx is a 4 digit number. The lowest value is xxxx=1148.

I write in my windows command shell, from the same folder as the .png files:

ffmpeg -f image2 -i NWAT_Vort_GB_%d.png movie.mpg

I'm getting the following error message:
"Could find no file with path "NWAT_Vort_GB_%d.png" and index in the range
0-4
NWAT_Vort_GB_%d.png: No such file or directory"

I think the problem is in how I specify the number string (%d), but not
sure as to the correct format. The files do exist ni the same directory, as
I have verified.

Any ideas as to the problem/correct format?

Thanks you!
Aviv