Python ArangoDB
If anyone gets the same error anytime in life, it was just a temporary error due to server overload.
I'm not able anymore to change my database on arangodb.
If I try to create a collection I get the error: 

Collection error: cannot create collection: invalid database directory

If I try to delete a collection I get the error: 

Couldn't delete collection.

Besides that some of the collections are now corrupted.
I've been working with this db for 2 months and I'm only getting these errors now.
Thanks.