CMS attachments can't be retrieved from remote source /upload failed
 

When I attempt to upload an attachment by linking to a remote image, i'm presented with the error:

"upload failed due to failure of writing temporary file"

I get across both of my websites... I'm presuming it's a folder permissions issue, but cannot locate further information.

This also occurs when I try to add an image (using the image function from the WYSIWYG editor) from a remote site with 'retreive remote file and reference locally' enabled.

Both give the same error, hence my thoughts that it is a chmod / permissions issue.

The /attachments directory is set to 777
the /packages/vbcms/attachments was set to 777 - but didn't help, so set back to 755 instead.

I'm sure it's a really simple thing I'm missing... but if someone would kindly point me in the right direction, I'd really appreciate it.