DB_SEC_E_AUTH_FAILED: Cannot insert Data into a table

From the name of the error I can say this is the security (authentication to be precise) issue. Do you have enough rights to modify this particular table.

Hello
i try to insert data into a table located in a DB on a MS-SQLServer. Unfortunally every time i try a INSERT INTO i get a DB_SEC_E_AUTH_FAILED
error.

My Connection string:
Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=db2;Data Source=HBR;Use Procedure for Prepare=1;Auto Translate=True;Packet Size=4096;Workstation ID=HBR; Use Encryption for Data=False;Tag with column collation when possible=False

This is the INSERT INTO:
INSERT INTO [_INITAB]
([dBDate],[dBVersion],[Compatibility],[ServerCompatibility],[Customer],[ApplicationVersion],[VersionComment],[DatabaseType])
VALUES (23-03-2006,'02.12.03',44,41,'','1','Empty database Database','application');

the DB is opened with this:
this.DestinationDbConnection.Mode = ADODB.ConnectModeEnum.adModeShareDenyNone;
this.DestinationDbConnection.CursorLocation = ADODB.CursorLocationEnum.adUseClient; // to prevent error -2147467259 (80004005), 'Could not update; currently locked.'
this.DestinationDbConnection.Open(null,null,null,0);

Can anyone tell me why i get this error?

Thanks
Matt