First check the security settings and share settings.
For databases on network computers, go to the level that is shared. Usually that is an entire drive. Right click on it and select "Sharing and Security". Make sure "Share this folder" is selected and there is a share name that does not have a dollar sign ($) behind it in the drop down box. (The dollar sign share is a default share for administrator only.) If there is not one, add it. Select a share without a dollar sign. Select permissions. Make sure the users that will be using the DB have change and read permissions.
Then right click on the folder(s) that contain the database(s) and select "Sharing and Security". Select security. Make sure the users have read, write, modify, and read & execute permissions. Select advanced. Edit the users that will access the databases. Make sure they have create files and delete permissions.
Then right click on the the database(s) and select "Sharing and Security". Select security. Make sure the users have read, write, modify, and read & execute permissions.