Locking files on Netware 5.1

After install Novell Netware 5.1 with SP5 – many DOS applications cannot work with files on network volumes: application tries to open a file on a network volume, but thus the file is blocked by the server and the application cannot get to it access any more. Access rights are all. On a network volume it is enough empty seat. On Novell 5.0 these applications are worked correctly