I have a site created with Drupal 6 (Pressflow). I just switched from a server with php 5.2 to php 5.3 each. Since I made ​​the change has appeared a curious error. My website is a social network where users can upload their user images. I use imagecache (6.x-2.0-rc1) for creating different sizes with which it can be seen that image (in a block, lists, etc.).
The error occurs only with the first 4 users were added to the social network. When you access your user profile or if any of these users (me and my brother) adds some content, presets images disappear (deleted from the imagecache folder). I add the images again and soon disappear, even if I upload the images from my ftp, disappear again. It only happens with this early 4 users, the rest does not have that problem.

Does anyone can help me?
What could be causing this error?

Regards
Barry Collins