This could be caused by the user attempting to enter a module for which they do not have rights to access, but more commonly it is a conflict between the user's options and their FE permissions.

1.) Go to Administration, Set up System Security.
2.) Open the effected user's profile. 
3.) Note which groups they are a part of.
4.) Open the User's Options on their profile. 
5.) Note on the General tab which part of which module is set up to open first when launching The Financial Edge application.
6.) Open the User's group and make sure that the items from step 5 are allowed in each group.

Note:  If the user's options are set to open into a module or part of a module that the user does not have permission to access, they will not be allowed in to The Financial Edge and they will continue to receive this error.