No, this would not cause a problem. A user could log into the books from different locations at the same time.
In regards to missing data, you should check for a file called NV20.LOG in the root of your NV2 program folder. It appends errors encountered while operating NV2. In many cases reorganizing the books from the NewViews 2.0 windows menu will solve the encountered errors.
Click Help > About either from the workstation or from within your application database to verify that you are using the most recent version of NV2. The current version is 2.08.16 (version 2.08 service pack 16). If you are using a prior version then get the latest version of NV2 from http://www.qwpage.com and install it on top of your current version.