In order to grant the ASPNET runtime access to your SQL database from the sqlcmd.exe command prompt you need to do the following:

— If permissions exist but are invalid, eg database copied from different machine:

Use mydatabase
Go

drop schema ASPNET
go

sp_droprolemember 'db_owner', ASPNET
go

drop user ASPNET
go

—Now Add back permissions for this machine:

sp_grantlogin 'MACHINENAME\ASPNET'
go

sp_grantdbaccess 'MACHINENAME\ASPNET', 'ASPNET'
go

Sp_addrolemember 'db_owner', 'ASPNET'
go

Alternatively, use the attached batch file which passes in the correct machine name