Can't change the contents of a table in SQL Server2005

[ayyazm64]

Hi,
I have a problem that in a database (named DDS) i can change or delete records in all tables but there is one which i can't. There isn't any foreigh keys(There is one dependencies, a view). So could you please tell me that is there any way that while designing a database in SQL Server we can lock a table and is there any way to open it and change the values of a field. There are two constraints as:

USE [DSS]
GO
ALTER TABLE [dbo].[tblGlob] DROP CONSTRAINT [DF_tblGlob_BYDEFT]

USE [DSS]
GO
ALTER TABLE [dbo].[tblGlob] DROP CONSTRAINT [DF_tblGlob_SetValue]

Even if i delete these constaints, still i can't change the data in this table.
Here is the image of error i get:-


The login has all rights for that database.
Is there any one who knows how to do this.

Ayyaz