Memcached won't increment a numeric value

[Josiah Ivey]

Using both the Dalli and Memcached-client gems, I am unable to
increment a numeric value:

ruby-1.9.2-p0 > CACHE = MemCache.new 'localhost:11211'
 => <MemCache: 1 servers, ns: nil, ro: false>
ruby-1.9.2-p0 > CACHE.set('abc', 123)
 => "STORED\r\n"
ruby-1.9.2-p0 > CACHE.get('abc')
 => 123
ruby-1.9.2-p0 > CACHE.incr('abc')
MemCache::MemCacheError: cannot increment or decrement non-numeric
value
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:926:in `raise_on_error_response!'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:831:in `block in cache_incr'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:865:in `call'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:865:in `with_socket_management'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:827:in `cache_incr'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:342:in `block in incr'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:886:in `with_server'
        from /Users/josiahivey/.rvm/gems/ruby-1.9.2-p0/gems/memcache-
client-1.8.5/lib/memcache.rb:341:in `incr'
        from (irb):6
        from /Users/josiahivey/.rvm/rubies/ruby-1.9.2-p0/bin/irb:17:in
`<main>'

Any ideas?