Preload next image problem

hi,

I am having trouble with adding some functionality to senoculars preloadnextimage.fla

The file basically loads a gallery image then preloads the next image to be displayed,after a preset delay(2 seconds in this case) the main image is replaced by the preloaded image.

my problem is that if the next image is not completely preloaded when the delay is up the functions starts again and try to preload the same file again…
(the small images used load very quickly so I use the bandwidth profiler on 56k to simulate my problem)

I could fix this by simply making the delay time longer but this is no good for how I plan to use this.

Hope I explained this correctly

Anyway here is the fla, hope its not too confusing - my actionscript skills are limited

hope someone can help
thanks,