SilkMeter should be installed in a location independent of all of your test machines. Or on one of the machines running SilkTest that isn't gonna move around a lot.
Each installation of SilkTest connects to the SilkMeter "server" to check out a license at launch, execution, etc. If you have 1 valid license, SilkMeter checks that one out to the requesting machine. As soon as another machine tries to check out a license, SilkMeter tells that machine, in essence, "Honk, thanks for playing, all licenses in use."
Tony's right: you can install SilkTest on a thousand machines. However, you can only launch as many as you have licenses for at any given time.
So, if you have 1 license and need 2, I would recommend that you contact your Segue sales representative and purchase another SilkTest license.
A concerned Borland customer, a fly in the ointment, a wrench in the works.