Bug found in "jdbc7.0-1.2.jar"

Hello:

When I execute the "executeUpdate" method ("PreparedStatement" class) with a
SQL statement: UPDATE or DELETE, always I receive '1', although the row
finded don't exist into the BD.

I have tried it with "pgjdbc2.jar" and works ok, though I have PostgreSQL
7.0.2 installed.

Could I have problems due to use this driver instead of "jdbc7.0.-1.2"?

Thank you very much,

Agustín Rodríguez