Command Line Remote Run for Mercurial Mapping

I cannot figure out what the .teamcity-mappings.properties file should contain.  I've tried everything...we use mercurial hosted on bitbucket and the branch is named Production, from instruction it should contain:

.=https://bitbucket.org/company/repository-name/branch/Production

That doesn't work, I get:

java.lang.IllegalArgumentException: No one of [bt3] configurations affected by collected changes
        at com.jetbrains.teamcity.command.RemoteRun.execute(RemoteRun.java:156)
        at com.jetbrains.teamcity.command.CommandRunner.run(CommandRunner.java:109)
        at com.jetbrains.teamcity.command.CommandRunner.main(CommandRunner.java:136)
Invalid parameter(s): No one of [bt3] configurations affected by collected changes

Can anyone shed some light here?