According to the http://tracker.firebirdsql.org/browse/CORE-6234
"In FB 3 the syntax of ALTER TRIGGER was changed to not allow to specify new type for DATABASE triggers."

For fixing this issue just remove the "ON CONNECT POSITION 0" line when alter a Database Trigger