networking (netman.dll) missing *.dll files

Hi, I have run into a problem with my Dell Optiplex gx1 running Win98SE.

A number of applications (Norton Anti-Virus 2005 among them) when attempting
to load, will respond with "Error starting program - netman.dll - not found"
and when I click on the ok button and repeats for a while, unless I close the
application with CTRL-ALT-DEL. I need to know if this netman.dll file was
ever part of Win98SE or if there is a patch or a windows upgrade file
containing same. As it is, I need this file to proerly configure Norton
Anti-Virus 2005. The machine came with optional onboard networking chipset.

Any help would be greatly appreciated.

P.S - If I need to upgrade the main Windows OS, please advise which
version of Windows has this file.