Problems with image upload

I have set permissions for the UPLOADS directory to read/write/modify and also set it for child objects.

When uploading images, I first see that the progress bar is not moving.
The second after, I get this error:
The URL for the error is: http://mydomain.net/forum/RTE_popup_adv_image.asp?PB=Y&PID=079E63BF076C38B9

This often indicates problems with permissions, but the funny thing is that if I close and reopen the "insert image" window, I'll find that the picture has been uploaded to the server anyway.
By FTP, I confirm that there has been created a directory containing the image and an XML-file.

So what is wrong then ?
Does other directories need permissions as well ?



Edited by Pilsener - 06 August 2011 at 12:50pm

If the image is being uploaded correctly and you are getting an error like this then I suspect the issue is that you have enabled image resizing in the forums upload settings in the admin area and your host does not support Persists AspJpeg used for resizing the image after the upload.

Use the server test tool in the admin area to see if you have Persists AspJpeg on the server. If not you need to disable the image resizing features on the upload image settings page.