Change back Net Type from TCPS to TCP


i dig a lot of posts and still can’t find what i need to know.

i meet a problem with net type. normally, users can connect using net type = tcp. until then the server was re-installed - and consequently re-configured. now users must connect using net type = tcps.
when users select tpc, the error message is:

The network is not functioning correctly. A ‘packet’ has been corrupted (a checksum error).
This error indicates that the network is not completely reliable. Please note how often this type of error occurs in the network. Contact your system manager if you need assistance.

what i’m looking for, is:
what i need to do to make the net type back to tcp?
is it only on nav db server configuration or there is something i need to do with server 2003?

thank you.

ps. NAV 4.03. windows server 2003

I also need to do the same for a NAV 2009 DB. Anyone?