When I double-click on the "smsimain" program to install version 2.0.148.00 of SMS Installer, I get a dialog box that says:
Setup has detected that this computer is not Microsoft Systems Management Server site server.
This installation can only be run on a site server.
How can I fix this or what does it mean?
As detailed in Rod Trent's "Extracting the SMS Installer Download on a Workstation" article, when you double-click on the executable it checks the value in the following Registry key:
By default this is set to "00000004" on a workstation with just the admin console installed.
Change this value to either "00000001" (for a Primary site) or "0000002" (for a Secondary site), then install SMS Installer then change the value back again to "00000004".