Saskia de Korte, I have taken a while to reply only because this is such a generic error despite I appreciate you are in package mode. And in my search and findings nothing seem to match what you have.

I see you are on a very old version of Studio. Have you managed to process packages from this supplier before? Do you happen to know what version of Studio they are using, as support for such an old version as yours cant be taken for granted and could be limited. 

If you like, you are welcome to share your package with me in a manner you deem safe and secure.

Lyds 

Hi Lydia,

Thanks for your reply. Yes, I realize my version of Studio is Old :) It's very likely that the supplier is using the newest version of Studio, but I did not encounter any problems before yesterday. I guess I just have to upgrade to the latest version.

Hi Lydia,

Thanks for your reply. Yes, I realize my version of Studio is Old :) It's very likely that the supplier is using the newest version of Studio, but I did not encounter any problems before yesterday. I guess I just have to upgrade to the latest version.

Saskia de Korte it is worth checking if they themselves performed an upgrade. Then looking at the latest release notes we may find some area's of incompatibility.
As I have so many versions of Studio installed I can check if I get this error with the package, unless you want to chat to your client first