[TYPO3] user (not admin) can't delete files, but he can add/change them

[Vandemaele David]

Hello,

I'm using the DAM extension, and I recently come across this problem:
A translator(some user) seems to have no permissions to delete a file.
He gets the following error: "The command given to this module is 
unknown. Command: tx_dam_cmd_filedelete"

But he can add one, create a new dir, change a file, etc...
I already checked the permissions, and they seem to be correct.

What am I missing here?

With kind regards,
David