Fix type error in port variable

Fixes the error...
debugger invoked on a TYPE-ERROR in thread
  The value 4005 is not of type STRING.

Environment...
Linux 3.2.0-4-amd64 #1 SMP Debian 3.2.46-1 x86_64 GNU/Linux
VIM - Vi IMproved 7.3 (debian package)
SBCL 1.0.57.0.debian