dash in hostname causes error

[mark]

I am using cfengine 2.1.10 on solaris 8.  I am trying to set a variable
based on the host I am on with the following statements:

control:
        
  hostname::
    variable_1 = ( value )
  
  host-name::
    variable_1 = ( value )

When I run cfagent, I get the following error message:

cf:cfengine::/var/cfengine/inputs/cf.groups:24: syntax error 
Stray character (-)Looking for an input file cf.main

When I comment out the lines for the hostname with the dash then
everything runs correctly.  

I have searched google and looked in the docs, but can't find any
reference to not using hostnames with dashes in them.  

Can anyone tell me what I am doing wrong or at least point me in the
right direction?

Thanks
Mark