This is the only thing I can think of, and it actually involves the domain name, so I don't know if it even applies to your real code.

In your example, you've got -domain=>'somedomain.com',. The CGI documentation states:

       2. a domain
           This is a partial or complete domain name for which
           the cookie is valid.  The browser will return the
           cookie to any host that matches the partial domain
           name.  For example, if you specify a domain name of
           ".capricorn.com", then the browser will return the
           cookie to Web servers running on any of the machines
           "www.capricorn.com", "www2.capricorn.com",
           "feckless.capricorn.com", etc.  Domain names must
           contain at least two periods to prevent attempts to
           match on top level domains like ".edu".  If no domain
           is specified, then the browser will only return the
           cookie to servers on the host the cookie originated
           from.
[download]

And I seem to recall having problems setting cookies in my own scripts, when I had specified the domain with a single period. So, try changing your code to -domain=>'.somedomain.com', and see if that fixes the problem.