Problem Modify and optimize an application

We have problem using modify application and optimize application on a specific application.

The application name is GPFormat.

When we do a modify application and choose "Reassign SQL Index" we get the following errror message:

Error message:: Cannot drop the index 'dbo.tblFACTGPFormat.IX_tblFACTGPFormat', because it does not exist or you do not have permission.

And if we do an optimize application with "Full Optimize" and "Compress database" we get the following errror message:

Error message:There is already an object named 'CONSTTBLFACTGPFORMAT' in the database.

Could not create constraint. See previous errors.

We using BPC 5,1 SP5 and SQL2005