I installed logic pro 9 - Yamaha grand piano is missing?

Dear all,

After I installed logic pro 9, I tried to reopen some old projects, but now it says:

EXS24 instrument "Yamaha Grand Piano.exs" not found

EXS24 instrument "Megfat_Superstrings.exs" not found

How can I find these instruments back?

Thank you in advance for help on this matter

Best regards

Roxor85