>I'm starting to get 'File Access Denied' errors when browsing tables in shared mode while the application is running on the NT network.

Part of your code must be locking a table exclusively.

>Also, my application launcher, which checks the version number and copies new exe from network to client if necessay, is acting weird too. Never had problems like this before and nothing has changed.

Start a new thread on this one listing what error messages you are getting with a short piece of code that is having the problem.