The installation order for most BackOffice products is at

The Windows NT Option Pack for Windows NT 4.0 (NTOP) requires that you view:

Q195015   Installation Conflicts with Service Pack 4.

Q194113   ErrMsg: Microsoft Internet Explorer 4.0 Setup - Some Services....

Q225307   Script debugger is not installed during SBS 4.5 upgrade if NTOP.

Q194507   Windows NT 4.0 Service Pack 4 Readme.txt File (40-bit).