seems i had some quite bad corruption throughout the database, i think it was caused by the fact that im using a template and the template was created in access '97, so ive had to convert it.
So i manually converted and manually split the database.
now i have a proper BE and FE, so ive fixed problem 3 and problem 1.
Could someone help me out with navigation customization (problem 2

). Ill elaborate a bit:
I dont want users to be confused when they look on the left and see hundreds of queries, forms, tables, reports etc. I want to know how to just see the forms they need to see. I know how to create a custom group and all that. But i dont want a phone call every 5 minutes from someone saying "ive got loads of crap on the left of my screen that i dont understand and cant find how to get back to what i was looking at" (because they have changed the view type to Object Type for example).