Playing an image sequence in reverse

[James W. <jfc...@ya...>]

Hi all,
 
I'm trying to run a JPEG image sequence in reverse order, but am running into problems:
 
Code:
 
cubic { "dummy1024.png", "dummy.png","dummy.png", "dummy.png", "dummy.png", "dummy.png" }
 
local anim = patch {face=1, x = 0, y = 0, image = "patches/anim_100.jpg" }
local animpos = 100
 
hotspotmap "hotspotmap.png"
 
hotspot {
onmousedown = function()
pipmak.schedule(
0.04,
function()
animpos = math.mod(animpos - 1, 101)
anim:setimage ("patches/anim_" .. animpos .. ".jpg")
return 0.04
end
)

end 
}
 
This playes it backward, but once it gets to frame "anim_0.jpg", it goes on to output continusly "Cannot find file "anim_-1.jpg" Cannot find file  "anim_-2.jpg", and so on.
How do I make it loop?
 
Thanks,
    James