Fixed port boundary checks

Ignore-this: 6d7025d94b3c27f80ba66109cd75aa65

darcs-hash:20101013053130-b22ec-a34da434f74f20ab6f87623b333983b6dc87fc00
Improved error messages

Ignore-this: bdeac6db18688f52dee2367dc92b4f9

darcs-hash:20101013075324-b22ec-3e29f90e9eb237d813542f6194804273233d9f4f