I think that I find the origin of the problem.
I remember you the problem (using OJS in Windows 2000 OS):
the authors get this error when press "finish submission":
DB Error: ERROR: invalid UTF-8 byte sequence detected near byte 0xe3
I get the same error when I try to save metadata.
I think that this is because the windows NT or 2000 use UCS-2 instead of UTF-8 internally.
I find this in the link
"UCS-2 and UTF-8 are two common ways to store bit patterns that represent Unicode characters. Microsoft Windows NT, SQL Server, Java, COM, and the SQL Server ODBC driver and OLEDB provider all internally represent Unicode data as UCS-2".
"Any UTF-8 data sent from the client to the server via GET or POST is also converted to UCS-2 automatically"
As I am not expert in computer science, please read the link and suggested me a solution of the problem.