think you have to go through all fields...

like jo said: single field in a table can have different collation from the table. There is no way

Of course you can do some reverse enginering: since when does this message appear in logs? which table\field was created then?

don't know a command that can set collation for all objects in one time. option might be to make a query whith a cursor that loop s through all sysobjects...nested cursor that finds all columns in a table and then execute an alter database command.. 

good luck