Imagecache showing just one time?

Hi

I'm using imagecache 5.x-2.4 in my site and it's working perfect with cck-imagefield.

Now I'm trying to use it also with inline but something is going wrong. I create a imagecache preset and I apply it to my teasers, when I reload the page the "imagecached" images are shown but after then, when I reload again the page the images doesn't appear.

I've checked the files in the server with my ftp client and the "imagecached" images are there. I've compared the files access privileges between the "righ" images and the "wrong" ones and everything is the same:

664 for files
744 for folders

If you try to access directly to the images you get different results:

imagecache image through cck-imagefield: http://pixelgordo.com/ficheros/imagecache/portadaversion/foto_caja/menac...? OK (what about the ending ? char?)
imagecache image through inline filter: http://pixelgordo.com/ficheros/imagecache/teaser/blog/1327/avatares360.jpg? (the file exists but it's no accessible)

The file access is set to public to the whole site through administer->configuration->file system

Any idea or suggestion about how to solve the problem? is it a bug from inline-imagecache?

Kind regards, thanks for the answers-ideas-suggestions... and sorry for my numerous mistakes writing in english ;)