Norton AntiVirus Corporate Edition 7.0

Using Symantec System Center, I attempted to remotely install the client software on about 20 systems. This worked on some of the PCs. But, on others the message says initializing remote installation, copying files, complete; however, these systems do not show up on the system hierarchy and the icon in their individual system trays shows an exclamation point, which means the installation did not complete. On still others, I get an error message that some files could not be copied and installation is aborted. All of the systems are running NT 4.0.