Errors are better added with indexes and not strings

Signed-off-by: emanuele <emanuele45@gmail.com>
Added removeError to attachment_error_context

Signed-off-by: emanuele <emanuele45@gmail.com>
 Case consistency attachment_error_context to Attachment_Error_Context

Signed-off-by: emanuele <emanuele45@gmail.com>
Merge pull request #1464 from emanuele45/attach_errors

Attach errors