The requested page could not be found. Intermittent error message.

Issue Summary

Hi, I installed the module the other week.
Since then I have included a block that shows recent pictures from my flickr account.
Everything was working fine until I noticed that the block sometimes decides not to load and gives the following error message "The requested page could not be found".
If I hit refresh again it loads properly and displays the images.
Anyone have any ideas? Is it timing out or something? If so how come it loads sometimes and then randomly decides not to?

Cheers,
Andrew.