problems creating a column

dear all,

I have been trying to create a test database with some columns to show
a colleague how pgadmin works. After creating, deleting some columns, we
tried to create a column of the serial data type. Then the system
complained with the following message:

"Adding columns with defaults is not implemented, Add the column, then
use Alter Table SET DEFAULT"

After playing around a little bit with the pgadmin tool I noticed that
sometimes some refresh is needed to perform the changes...Maybe this
error message is because I did not issued the changes doing a refresh?

By the way, this error messages cannot be translated?

Thanks in advance

Miguel