error 229

Hi
Actually this question is related to SQL Server 2000.

This error occured when i followed these steps:

Started Enterprise Manager >> My SQL Server Group >> MyDatabase(diamond) >> Tables

Error 229:
1) SELECT permission denied on object 'sysobjects', database 'diamond', owner 'dbo'.
1) SELECT permission denied on object 'sysindexes', database 'diamond', owner 'dbo'.


After then when i right clicked MyDatabase(diamond) >> properties

again the same error but with different objects - sysfiles, sysusers, sysfilegroups


I am new to SQL Server 2000.
Can anybody pls tell me what to do next.