Your user does not have access rights to the SQL server he/she needs to perform the SQL Server task requested.

MS SQL can be installed different ways - it can use Windows authentication, its own passwords and user list or a mixed model with the union of both of these. You need to know how the SQL Server's authentication works, then find out if the user has properly accessed the server with the user credentials he/she supplied. Also be aware that any admin user can come along and make even table specific security rules.